Giant magnetoimpedance(GMI)sensors are increasingly employed in modern magnetic sensing technologies.However,improving the GMI performance of magnetic cores remains challenging due to intrinsic limitations in material...Giant magnetoimpedance(GMI)sensors are increasingly employed in modern magnetic sensing technologies.However,improving the GMI performance of magnetic cores remains challenging due to intrinsic limitations in material properties and structural stability.In this work,we explore the use of Joule heating to enhance the GMI response of Fe_(20)Ni_(80)/Cu composite wires.By applying a current of 1.8 A for 10 min,notable improvements in magnetic domain uniformity and a reduction in domain spacing are observed.Under these conditions,GMI ratios reach 1870% in the non-diagonal mode and1147%in the diagonal mode,respectively,highlighting their potential for applications in high-precision weak magnetic field sensing.展开更多
To investigate the aging mechanisms and elucidate the correlations between unstable microstructure and performance in biodegradable Zn alloys,the accelerated aging experiment was conducted on a high-performance wrough...To investigate the aging mechanisms and elucidate the correlations between unstable microstructure and performance in biodegradable Zn alloys,the accelerated aging experiment was conducted on a high-performance wrought Zn−0.1Mg alloy by annealing at 200℃ for varying durations.The findings reveal that the tensile strength of the alloy rapidly and significantly declines with prolonged annealing time,decreasing from 383 MPa for the as-received alloy to 102 MPa for the alloy subjected to 1440 min of annealing.The primary factors contributing to this considerable reduction in strength are static recrystallization,grain coarsening,and dislocation annihilation.Initially,the ductility of the alloy shows fluctuations,ultimately experiencing a marked decrease after extended annealing.This decline is linked to the grain growth and heightened texture intensity,while the unusual increase in ductility observed between 30 and 120 min of annealing is likely due to the formation of twins.In addition,due to rapid grain growth and an increase in precipitates and twins,the corrosion resistance of the alloy in Hank’s solution has worsened,with the corrosion rate rising from 0.037 to 0.069 mm/a following 300 min of annealing.展开更多
350 keV He^(+) ions were injected into laser powder bed fusion(LPBF)-processed 304L stainless steel and traditional rolled 304L stainless steel with a flux of 1×10^(17) ions/cm^(2) at room temperature,followed by...350 keV He^(+) ions were injected into laser powder bed fusion(LPBF)-processed 304L stainless steel and traditional rolled 304L stainless steel with a flux of 1×10^(17) ions/cm^(2) at room temperature,followed by annealing at 750℃ for 10,100,and 300 h,respectively.The results showed that material swelling due to helium bubble coarsening was almost not observed in either the LPBF or rolled samples after 10 h of annealing duration.Rapid coarsening and swelling of bubbles occurred in the rolled samples,but only moderate bubble growth occurred in the LPBF sample after annealing for 100 h.After annealing for 300 h,the helium bubbles in both samples tended to grow steadily.For 10 h of annealing,the irradiated samples were in a disequilibrium state,and the apparent activation energy(E^(act))calculated by the Arrhenius model determined that helium atoms tended to diffuse through the displacement mechanism,and helium bubbles grew under the migration and coalescence(MC)mechanism.With annealing times over 100 h,the high-density dislocations and nano-oxide particles in the LPBF sample still had a strong trapping effect on the movement and growth of helium bubbles.After annealing for 300 h,the cellular subgrains in the LPBF sample decomposed,and the nano-oxide particles had no trapping effect on the helium bubbles.At this time,the dislocation structure played a primary role in suppressing the growth of helium bubbles,and the radiation resistance of the LPBF sample remained superior to that of the rolled samples.展开更多
The interfacial properties of Schottky contacts crucially affect the performance of power devices. While a few studies have explored the impact of fluorine on Schottky contacts, a comprehensive theoretical explanation...The interfacial properties of Schottky contacts crucially affect the performance of power devices. While a few studies have explored the impact of fluorine on Schottky contacts, a comprehensive theoretical explanation supported by experimental evidence remains lacking. This work investigates the effects of fluorine incorporation and electrothermal annealing(ETA) on the current transport process at Ni/β-Ga_(2)O_(3) Schottky contacts. X-ray photoelectron spectroscopy and first-principles calculations confirm the presence of fluorine substitutions for oxygen and oxygen vacancies and their lowering effect on the Schottky barrier heights. Additionally, accurate electrothermal hybrid TCAD simulations validates the extremely short-duration high temperatures(683 K) induced by ETA, which facilitates lattice rearrangement and reduces interface trap states. The interface trap states are quantitatively resolved through frequency-dependent conductance technique, showing the trap density(DT)reduction from(0.88-2.48) × 10^(11) cm^(-2)·eV^(-1) to(0.46-2.09) × 10^(11) cm^(-2)·eV^(-1). This investigation offers critical insights into the β-Ga_(2)O_(3) contacts with the collaborative treatment and solids the promotion of high-performance β-Ga_(2)O_(3) power devices.展开更多
Efficient multiple unmanned aerial vehicles(UAVs)path planning is crucial for improving mission completion efficiency in UAV operations.However,during the actual flight of UAVs,the flight time between nodes is always ...Efficient multiple unmanned aerial vehicles(UAVs)path planning is crucial for improving mission completion efficiency in UAV operations.However,during the actual flight of UAVs,the flight time between nodes is always influenced by external factors,making the original path planning solution ineffective.In this paper,the multi-depot multi-UAV path planning problem with uncertain flight time is modeled as a robust optimization model with a budget uncertainty set.Then,the robust optimization model is transformed into a mixed integer linear programming model by the strong duality theorem,which makes the problem easy to solve.To effectively solve large-scale instances,a simulated annealing algorithm with a robust feasibility check(SA-RFC)is developed.The numerical experiment shows that the SA-RFC can find high-quality solutions within a few seconds.Moreover,the effect of the task location distribution,depot counts,and variations in robustness parameters on the robust optimization solution is analyzed by using Monte Carlo experiments.The results demonstrate that the proposed robust model can effectively reduce the risk of the UAV failing to return to the depot without significantly compromising the profit.展开更多
Block copolymer(BCP) nanolithography offers potential beyond traditional photolithographic limits, yet reliably producing low-defect, perpendicular domains remains challenging. We introduce a microenvironmentdriven is...Block copolymer(BCP) nanolithography offers potential beyond traditional photolithographic limits, yet reliably producing low-defect, perpendicular domains remains challenging. We introduce a microenvironmentdriven isothermal annealing method for directed self-assembly of BCP thin films. By annealing films at stable temperature in a quasi-sealed, inert-gas chamber, our approach promotes highly uniform perpendicular lamellar nanopatterns over large areas, effectively mitigating environmental fluctuations and emulating solvent-vapor annealing without solvent exposure. Resulting BCP structures demonstrate enhanced spatial coherence and notably low defect density. Furthermore, we successfully transfer these nanopatterns into precise metal nano-line arrays,confirming the method's capability for high-fidelity pattern replication. This scalable, solvent-free technique provides a robust, reliable route for high-resolution nanopatterning in advanced semiconductor manufacturing.展开更多
In this work,the TiO_(2)/Sb_(2)S_(3) nanorod arrays(NRAs)were synthesized through a two-stage hydrothermal route for photoelectrochemical(PEC)water splitting.The effect of annealing treatment in Ar ambience on the PEC...In this work,the TiO_(2)/Sb_(2)S_(3) nanorod arrays(NRAs)were synthesized through a two-stage hydrothermal route for photoelectrochemical(PEC)water splitting.The effect of annealing treatment in Ar ambience on the PEC activity of TiO_(2)/Sb_(2)S_(3) composite sample was investigated by electrochemical impedance analysis,including Nyquist and Mott-Schottky(M-S)plots.It was demonstrated that vacuum annealing could crystallize Sb_(2)S_(3) component and change its color from red to black,leading to an increment of photocurrent density from 1.9 A/m^(2) to 4.25 A/m^(2) at 0 V versus saturated calomel electrode(VSCE).The enhanced PEC performance was mainly attributed to the improved visible light absorption.Moreover,annealing treatment facilitated retarding the electron-hole recombination occurred at the solid/liquid interfaces.Our work might provide a novel strategy for enhancing the PEC performance of a semiconductor electrode.展开更多
As-forged WSTi6421 titanium alloy billet afterβannealing was investigated.Abnormally coarse grains larger than adjacent grains could be observed in the microstructures,forming abnormal grain structures with uneven si...As-forged WSTi6421 titanium alloy billet afterβannealing was investigated.Abnormally coarse grains larger than adjacent grains could be observed in the microstructures,forming abnormal grain structures with uneven size distribution.Through electron backscattered diffraction(EBSD),the forged microstructure at various locations of as-forged WSTi6421 titanium alloy billet was analyzed,revealing that the strength of theβphase cubic texture generated by forging significantly influences the grain size afterβannealing.Heat treatment experiments were conducted within the temperature range from T_(β)−50°C to T_(β)+10°C to observe the macro-and micro-morphologies.Results show that the cubic texture ofβphase caused by forging impacts the texture of the secondaryαphase,which subsequently influences theβphase formed during the post-βannealing process.Moreover,the pinning effect of the residual primaryαphase plays a crucial role in the growth ofβgrains during theβannealing process.EBSD analysis results suggest that the strength ofβphase with cubic texture formed during forging process impacts the orientation distribution differences ofβgrains afterβannealing.Additionally,the development of grains with large orientations within the cubic texture shows a certain degree of selectivity duringβannealing,which is affected by various factors,including the pinning effect of the primaryαphase,the strength of the matrix cubic texture,and the orientation relationship betweenβgrain and matrix.Comprehensively,the stronger the texture in a certain region,the less likely the large misoriented grains suffering secondary growth,thereby aggregating the difference in microstructure and grain orientation distribution across different regions afterβannealing.展开更多
Pre-stretching and annealing treatments were conducted on twin roll cast Mg-2Al-1Zn-1Ca(AZX211,in wt.%)plates with a rare earth-like texture.Varying amounts of deformation were applied along the rolling direction(RD)a...Pre-stretching and annealing treatments were conducted on twin roll cast Mg-2Al-1Zn-1Ca(AZX211,in wt.%)plates with a rare earth-like texture.Varying amounts of deformation were applied along the rolling direction(RD)and transverse direction(TD)of AZX211 alloy in order to modify its mechanical proper-ties at room temperature.The results demonstrate that pre-stretching treatment effectively enhances the yield strength(YS),especially along the RD.The strengthening mechanism is attributed to the production of a large number of dislocations and sub-grain boundaries,but the work-hardening ability of the plate will be greatly weakened.Additionally,annealing treatment substantially improves the plasticity and in-plane anisotropy and restores the work-hardening ability.The notable distinction in the pre-stretching process between different directions lies in the underlying deformation mechanism.In case of RD,de-formation is predominantly governed by the slip mechanism of{0002}{11−20}basal slip and{10−10}{11−20}prismatic slip,while along the TD,deformation is primarily controlled by{0002}{11−20}basal slip without significant twinning deformation.When a 6%pre-stretching is conducted,the initial rare earth-like texture of the sample transforms into a symmetrically distributed double-peak basal texture,accompanied by grain refinement.This texture transformation is chiefly due to the dominance of{0002}{11−20}basal slip-driven deformation.Moreover,the annealed sample maintains a strong basal texture,owing to strain-induced recrystallization.展开更多
The effect of hot band annealing processes—batch annealing and continuous annealing—on the texture evolution and ridging performance of ferritic stainless steel was investigated.The surface and central layers of the...The effect of hot band annealing processes—batch annealing and continuous annealing—on the texture evolution and ridging performance of ferritic stainless steel was investigated.The surface and central layers of the hot band exhibited strong shear and plane deformation textures,respectively.After batch annealing,the texture intensity of the hot-rolled sheet texture significantly decreased,and a weak recrystallization texture appeared,while fully recrystallized grains occurred after continuous annealing.A complete recrystallized{111}texture was obtained after recrystallization annealing.The sheet subjected to continuous annealing exhibited the highest intensity of{111}texture,which was accompanied by a dispersed grain orientation distribution,resulting in the lowest ridging height.展开更多
The microstructures and corrosion behavior of 1.0wt%Gd-containing neutron-absorbing duplex stainless steel annealed at different temperatures were studied.Results reveal that the content of Gd-containing secondary pha...The microstructures and corrosion behavior of 1.0wt%Gd-containing neutron-absorbing duplex stainless steel annealed at different temperatures were studied.Results reveal that the content of Gd-containing secondary phase increases with increasing the annealing temperatures to 1080℃,and then decreases.In the sample annealed at 1080℃,M-Gd(M=Fe,Cr,Ni)intermetallic with M_(3)Gd as the core phase and M_(12)Gd as the shell is the primary secondary phase.In the sample annealed at 1140℃,M_(3)Gd phase is dominant.The corrosion behavior of the two annealed steel samples were analyzed in NaCl,HCl and H_(3)BO_(3) solutions.It is found that the sample annealed at 1140℃ has lower corrosion rate.M_(3)Gd is more electrochemically active than M_(12)Gd when the sample is immersed in NaCl and HCl solutions,but more noble in H_(3)BO_(3) solution.展开更多
In this work,the properties and microstructure of sintered Nd-Pr-Fe-Co-Zr-Ga-Cu-B magnet prepared by the single-step annealing,double-step annealing,and triple-step annealing processes were studied.The triple-step ann...In this work,the properties and microstructure of sintered Nd-Pr-Fe-Co-Zr-Ga-Cu-B magnet prepared by the single-step annealing,double-step annealing,and triple-step annealing processes were studied.The triple-step annealed magnet exhibits the highest intrinsic coercivity of 19.72 kOe,which is a 58.5%enhancement relative to the as-sintered magnet,and has the best temperature stability of coercivity.The best continuity of grain boundary(GB)phase and the highest content of RE6Fe13Ga phase can be observed in the triple-step annealed magnet,along with relatively small grain size.After triple-step annealing process,the phase separation occurs at the triple-junction(TJ)region of the magnet,which is the Fe-rich phase identified as RE6Fe13Ga and the Fe-poor phase identified as Ia-RE_(2)O_(3).The Ia-RE_(2)O_(3)phase located at the corner of the TJ region can extend between the grains of(Nd,Pr)_(2)Fe_(14)B main phase to form the GB phase with a Fe content of less than 15 at%,thereby enhancing the magnetic isolation effect.The lattice misfit between the Ia-RE_(2)O_(3)phase and the adjacent main phase is less than 5%,which is helpful to reduce defects at the edges of the main phase grains,thus reducing the nucleation of reverse domains.展开更多
A high-purity Ti sheet with dense preexisting twins(introduced by 10%cold rolling)was subjected to isochronal annealing at 500–800°C for 1 h and isothermal annealing at 600°C for 0.17–100 h,respectively.By...A high-purity Ti sheet with dense preexisting twins(introduced by 10%cold rolling)was subjected to isochronal annealing at 500–800°C for 1 h and isothermal annealing at 600°C for 0.17–100 h,respectively.By mainly utilizing electron backscatter diffraction(EBSD)and electron channel contrast(ECC)imaging techniques,the microstructure and texture evolution during the isochronal and isothermal annealing were investigated systematically.Results show that recrystallization nuclei appear in the specimen annealed at 600°C for 1 h.In contrast,recrystallization cannot be initiated for those annealed at lower temperatures or for a shorter time.With the increase in temperature or time,the fraction of the recrystallized structure increases with gradual grain coarsening.Nearly complete recrystallization is reached after 800°C-1 h or 600°C-100 h annealing.Due to the distribution heterogeneity of microstructure and stored energy induced by the dense preexisting twins,recrystallization nucleation preferentially occurs in some specific regions(twin-twin or twin-grain boundary junctions).Then,they selectively consume twin lamellar structures,leading to non-uniform grain growth.It is demonstrated that the recrystallization nucleation is dominated by the strain-induced boundary migration mechanism,allowing scattered texture components corresponding to the twin lamellar structures to be gradually encroached by those untwinned structures with the initial bimodal basal texture(BBT).Eventually,a strong BBT is always obtained after sufficient recrystallization.展开更多
Two-dimensional transition metal dichalcogenides(TMDs)show great promise for developing the next generation of electronic and optoelectronic devices.However,most TMDs have n-type or n-dominant bipolar characteristics,...Two-dimensional transition metal dichalcogenides(TMDs)show great promise for developing the next generation of electronic and optoelectronic devices.However,most TMDs have n-type or n-dominant bipolar characteristics,and this severely limits their potential for being designed as multi-functional heterostructures.Recently,thermal annealing has been reported as an easy means of p-doping TMDs,but the mechanism remains ambiguous,thereby preventing reliable outcomes and it becoming a mature doping technology for TMDs.Here,the mechanism of thermal annealing for p-doping a 2D selenide is investigated thoroughly,revealing the key role of the catalytic effect of nano-thick gold electrodes in achieving p-doping.As an example,2D SnSe_(2)with a fairly high electron density of∼10^(18)cm^(−3)is used,and its electrical performance is greatly enhanced after thermal annealing when 30-nm-thick gold electrodes are deposited.The results of performing XPS and Auger electron spectroscopy on samples before and after annealing show that the p-doping effect is due to the oxidation of selenide atoms,during which the gold acts as a critical catalytic element.This method is also shown to be valid for other 2D selenides including WSe_(2)and MoSe_(2),and the present findings offer new avenues for enriching the electrical properties of 2D selenides by means of annealing.展开更多
A series of as-cast Si_(x)Al_(0.43)CoCrFeNi_(2.1)(x=0,0.1,0.2,and 0.3)high-entropy alloys(HEAs)was successfully fabricated by va-cuum-assisted melting.The phase constituents,microstructural features,and mechanical pro...A series of as-cast Si_(x)Al_(0.43)CoCrFeNi_(2.1)(x=0,0.1,0.2,and 0.3)high-entropy alloys(HEAs)was successfully fabricated by va-cuum-assisted melting.The phase constituents,microstructural features,and mechanical properties(including hardness,tensile behavior,and wear behavior)of alloys with various Si contents were evaluated.The results revealed that the addition of Si promoted the precipita-tion of a body-centered cubic 1(BCC1)phase enriched in Al,Ni,and Si with a B2-ordered structure.Furthermore,the secondary BCC2 phase was enriched with Cr,Fe,and Si precipitates within the BCC1 matrix.Ultimately,a multiphase face-centered cubic(FCC)/(BCC1/BCC2)structure was formed.The microstructural evolution driven by Si addition significantly enhanced the mechanical properties of the Si_(x)Al_(0.43)CoCrFeNi_(2.1) HEAs.As the Si content increased,the microhardness and tensile strength improved by approxim-ately 42%and 55%,reaching 2.359 GPa and 785 MPa,respectively.The quantitative evaluation of the various strengthening mechanisms indicated that the intrinsic hardness of the FCC matrix and hardening due to BCC1/BCC2 precipitation dominated the overall microhard-ness.The comparison of the energy barriers indicates that BCC2 primarily strengthens the alloy through a shear mechanism rather than an Orowan bypass mechanism.Furthermore,with increasing Si content,reduced friction and wear,together with smoother worn surfaces,re-flect a greatly enhanced wear resistance.After the optimal cold-rolling and 1 h annealing at 800℃,the Si_(0.3)Al_(0.43)CoCrFeNi_(2.1) alloy showed 56%and 62%increases in microhardness and tensile strength,respectively,compared to the as-cast state,reaching 3.68 GPa and 1270 MPa.The enhanced mechanical properties are attributed to the synergistic effects of residual strain hardening by FCC ordering and L1_(2)/BCC precipitation strengthening.展开更多
The emergence of additive manufacturing technology,particularly laser powder bed fusion,has revitalized NiTi alloy production.However,challenges arise regarding its mechanical properties and diminishing shape memory e...The emergence of additive manufacturing technology,particularly laser powder bed fusion,has revitalized NiTi alloy production.However,challenges arise regarding its mechanical properties and diminishing shape memory effect,which hinder its widespread application.Heat treatment has been identified as a method to enhance the performance of metallic materials in the realm of additive manufacturing.This process eliminates residual stress and enhances performance through precipitation strengthening.This study conducted a comprehensive annealing investigation on NiTi alloys to explore the impact of annealing time and temperature on the phase transformation behavior and shape memory performance.The mechanism underlying the performance enhancement was analyzed using scanning electron microscopy,energy-dispersive X-ray spectroscopy,electron backscatter diffraction,and transmission electron microscopy.The findings revealed that different annealing conditions resulted in multistep phase transformation behavior,with the 500℃-5 h sample exhibiting the best mechanical properties owing to the formation of nanoscale dispersed precipitates like Ni_(4)Ti_(3).However,higher temperatures led to larger precipitates,significantly weakening the properties of the NiTi alloy.Additionally,the annealing treatment did not have a notable impact on the grain size,texture strength,or direction.This study provides valuable insights for optimizing the heat treatment process of LPBF-NiTi alloys.展开更多
Semicrystalline polymers usually undergo multilevel microstructural evolutions with annealing and stretching processes,which is es-sential to tailor the physical properties of the polymer.Here,poly(butylene carbonate)...Semicrystalline polymers usually undergo multilevel microstructural evolutions with annealing and stretching processes,which is es-sential to tailor the physical properties of the polymer.Here,poly(butylene carbonate)(PBC)sheets were prepared via isothermal annealing and unidirectional pre-stretching processes,then the changes of PBC in crystallinity,mechanical properties,thermal properties and microscopic changes before and after annealing and stretching were measured,as well as the relationship between microstructure and macroscopic proper-ties before and after stretching.The strengthening mechanism of PBC was also described.It was demonstrated that shish-kabab structure emerged under the pre-stretching process.With the increase of the tensile ratio,the crystallinity,structure and mechanical properties are in-creased differently.Among them,the crystallinity and tensile strength after annealing-stretching treatment increased to 24.45%and 104.5 MPa,respectively,which were about 1.55 times and 3.4 times of those-without any treatment.展开更多
The effect of cryogenic treatment(CT)and relaxation annealing on the average nearest neighboring distance of atom(dm),ther-modynamic stability,soft magnetic properties,microhardness(Hv),and corrosion resistance of as-...The effect of cryogenic treatment(CT)and relaxation annealing on the average nearest neighboring distance of atom(dm),ther-modynamic stability,soft magnetic properties,microhardness(Hv),and corrosion resistance of as-spun(Fe_(0.5)Co_(0.5))_(75)B_(21)Nb_(4) metallic glasses(MGs)is studied.On the premise of maintaining a fully amorphous phase,appropriate CT and relaxation annealing are conducive to achieving the synergistic effect of increasing saturation magnetization(M_(s))and reducing coercivity(H_(c)).Shallow CT at 213 K optim-ally enhances the soft magnetic properties of MGs.Given its low activation energy of nucleation and increased activation energy of growth,appropriate CT is beneficial for achieving uniform annealed nanocrystals in amorphous phases.The correlation between free volumes(FVs)and potential energy suggests that the variation in Hc depends on the expansion and contraction behavior of amorphous phases after different CT processes.The fitting formulas of H_(c)–d_(m) and Ms–Hv correlations demonstrate that soft magnetic parameters have a solid linear relationship with the contents of FVs and degree of dense random packing.Moreover,pitting resistance is improved by ap-propriate CT and relaxation annealing.This improvement is characterized by the promotion of the stability of the Nb-rich passive film formed during electrochemical corrosion in 3.5wt%NaCl solution.展开更多
This study comprehensively investigates the effects of annealing on the structural,electrochemical properties and passivation film characteristics of Ti_(20)Zr_(20)Hf_(20)Be_(20)Ni_(20)(at%)high-entropy metallic glass...This study comprehensively investigates the effects of annealing on the structural,electrochemical properties and passivation film characteristics of Ti_(20)Zr_(20)Hf_(20)Be_(20)Ni_(20)(at%)high-entropy metallic glass(HE-MG).Subjected to various annealing temperatures,the samples were analyzed in a 3.5 wt%NaCl solution to evaluate changes in their microstructure and assess their corrosion resistance.Findings reveal that the HE-MG undergoes multistage crystallization,displaying an amorphous matrix integrated with face centered cubic(FCC)and Ni_(7)Zr_(2)phases between 420 and 500℃,indicating robust thermal stability.Electrochemical assessments identify a critical temperature threshold:Below the glass transition temperature(Tg),the HE-MG maintains excellent corrosion resistance,promoting stable passivation layers.Above Tg,enhanced long-range atomic rearrangement during relaxation increases passivation layer defects and significantly diminishes corrosion resistance.X-ray photoelectron spectroscopy(XPS)analyses show that the primary components of the passivation layer are TiO_(2),ZrO_(2),HfO_(2)and BeO.Increased annealing temperatures lead to enhanced Be and Ni content and decreased Ti,Zr and Hf.Additionally,high mixing entropy and significant atomic size mismatch suppress long-range atomic rearrangement and crystallization.The crystallization begins above Tg by_(20)℃,with crystalline phases evenly distributed within the matrix without drastically affecting corrosion resistance.This investigation highlights the impact of thermal treatment on the properties of HE-MG,contributing valuable insights into optimizing their performance and applications.展开更多
Twinning-induced plasticity (TWIP) steel shows great potential in engineering due to its excellent strength and ductility synergy, and strengthening research on its corrosion resistance and high-temperature oxidation ...Twinning-induced plasticity (TWIP) steel shows great potential in engineering due to its excellent strength and ductility synergy, and strengthening research on its corrosion resistance and high-temperature oxidation resistance is critical for broader applications. Herein, the effect of annealing temperature on the high-temperature oxidation and corrosion behavior of Fe-Mn-Cr-Al-Cu-C TWIP steel is investigated. The results show that increasing the annealing temperature from 700℃ to 1100℃ reduced the mass gain of the TWIP steel oxidized at 800℃ for 8 h from 1.93 to 0.58 mg·cm^(−2). Additionally, the self-corrosion current density decreases from 6.52 × 10^(−6) to 1.32 × 10^(−6) A·cm^(−2), while charge transfer resistance increases from 1461 to 3339 Ω·cm^(−2). The reduction in grain boundaries and dislocation density in the TWIP steel attributed to the increase in annealing temperature inhibits short-circuit diffusion, local galvanic corrosion and pitting, ultimately improving both oxidation and corrosion resistance. Moreover, high-temperature annealing prevents the formation of carbon-rich compounds and ensures uniform element distribution. The accumulation of Cu and Cu-rich products formed at the interface further protects against Cl− erosion, inhibiting pitting and local corrosion, thus enhancing the corrosion resistance of the TWIP steel.展开更多
基金supported by the State Key Research and Development Program,Special Gravity Wave(Grant No.2023YFC2206003)the Gansu Provincial Science and Technology Program Funding(Grant No.24JRRA499)+1 种基金the Natural Science Foundation of Shandong Province(Grant No.ZR2024QB219)the Lanzhou City Science and Technology Program Project(Grant No.2025-2-47)。
文摘Giant magnetoimpedance(GMI)sensors are increasingly employed in modern magnetic sensing technologies.However,improving the GMI performance of magnetic cores remains challenging due to intrinsic limitations in material properties and structural stability.In this work,we explore the use of Joule heating to enhance the GMI response of Fe_(20)Ni_(80)/Cu composite wires.By applying a current of 1.8 A for 10 min,notable improvements in magnetic domain uniformity and a reduction in domain spacing are observed.Under these conditions,GMI ratios reach 1870% in the non-diagonal mode and1147%in the diagonal mode,respectively,highlighting their potential for applications in high-precision weak magnetic field sensing.
基金supported by the National Natural Science Foundation of China(No.52271101)Suzhou Science and Technology Project,China(Nos.SYG202312,SJC2023005,SZS2023023)+1 种基金Nanjing Major Science and Technology Project,China(No.202309015)the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology,China(No.ASMA202305)。
文摘To investigate the aging mechanisms and elucidate the correlations between unstable microstructure and performance in biodegradable Zn alloys,the accelerated aging experiment was conducted on a high-performance wrought Zn−0.1Mg alloy by annealing at 200℃ for varying durations.The findings reveal that the tensile strength of the alloy rapidly and significantly declines with prolonged annealing time,decreasing from 383 MPa for the as-received alloy to 102 MPa for the alloy subjected to 1440 min of annealing.The primary factors contributing to this considerable reduction in strength are static recrystallization,grain coarsening,and dislocation annihilation.Initially,the ductility of the alloy shows fluctuations,ultimately experiencing a marked decrease after extended annealing.This decline is linked to the grain growth and heightened texture intensity,while the unusual increase in ductility observed between 30 and 120 min of annealing is likely due to the formation of twins.In addition,due to rapid grain growth and an increase in precipitates and twins,the corrosion resistance of the alloy in Hank’s solution has worsened,with the corrosion rate rising from 0.037 to 0.069 mm/a following 300 min of annealing.
基金supported by the National Natural Science Foundation of China(Nos.U22B2067 and 52073176).
文摘350 keV He^(+) ions were injected into laser powder bed fusion(LPBF)-processed 304L stainless steel and traditional rolled 304L stainless steel with a flux of 1×10^(17) ions/cm^(2) at room temperature,followed by annealing at 750℃ for 10,100,and 300 h,respectively.The results showed that material swelling due to helium bubble coarsening was almost not observed in either the LPBF or rolled samples after 10 h of annealing duration.Rapid coarsening and swelling of bubbles occurred in the rolled samples,but only moderate bubble growth occurred in the LPBF sample after annealing for 100 h.After annealing for 300 h,the helium bubbles in both samples tended to grow steadily.For 10 h of annealing,the irradiated samples were in a disequilibrium state,and the apparent activation energy(E^(act))calculated by the Arrhenius model determined that helium atoms tended to diffuse through the displacement mechanism,and helium bubbles grew under the migration and coalescence(MC)mechanism.With annealing times over 100 h,the high-density dislocations and nano-oxide particles in the LPBF sample still had a strong trapping effect on the movement and growth of helium bubbles.After annealing for 300 h,the cellular subgrains in the LPBF sample decomposed,and the nano-oxide particles had no trapping effect on the helium bubbles.At this time,the dislocation structure played a primary role in suppressing the growth of helium bubbles,and the radiation resistance of the LPBF sample remained superior to that of the rolled samples.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62174019, 52302046, L2424216)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2024A1515012139)+2 种基金the Major Program (JD) of Hubei Province (Grant No. 2023BAA009)the Knowledge Innovation Program of Wuhan-Shuguang Project (Grant No. 2023010201020262)the Basic Research Program of Jiangsu (Grant No. BK20230268)。
文摘The interfacial properties of Schottky contacts crucially affect the performance of power devices. While a few studies have explored the impact of fluorine on Schottky contacts, a comprehensive theoretical explanation supported by experimental evidence remains lacking. This work investigates the effects of fluorine incorporation and electrothermal annealing(ETA) on the current transport process at Ni/β-Ga_(2)O_(3) Schottky contacts. X-ray photoelectron spectroscopy and first-principles calculations confirm the presence of fluorine substitutions for oxygen and oxygen vacancies and their lowering effect on the Schottky barrier heights. Additionally, accurate electrothermal hybrid TCAD simulations validates the extremely short-duration high temperatures(683 K) induced by ETA, which facilitates lattice rearrangement and reduces interface trap states. The interface trap states are quantitatively resolved through frequency-dependent conductance technique, showing the trap density(DT)reduction from(0.88-2.48) × 10^(11) cm^(-2)·eV^(-1) to(0.46-2.09) × 10^(11) cm^(-2)·eV^(-1). This investigation offers critical insights into the β-Ga_(2)O_(3) contacts with the collaborative treatment and solids the promotion of high-performance β-Ga_(2)O_(3) power devices.
基金supported by the National Natural Science Foundation of China(72571094,72271076,71871079)。
文摘Efficient multiple unmanned aerial vehicles(UAVs)path planning is crucial for improving mission completion efficiency in UAV operations.However,during the actual flight of UAVs,the flight time between nodes is always influenced by external factors,making the original path planning solution ineffective.In this paper,the multi-depot multi-UAV path planning problem with uncertain flight time is modeled as a robust optimization model with a budget uncertainty set.Then,the robust optimization model is transformed into a mixed integer linear programming model by the strong duality theorem,which makes the problem easy to solve.To effectively solve large-scale instances,a simulated annealing algorithm with a robust feasibility check(SA-RFC)is developed.The numerical experiment shows that the SA-RFC can find high-quality solutions within a few seconds.Moreover,the effect of the task location distribution,depot counts,and variations in robustness parameters on the robust optimization solution is analyzed by using Monte Carlo experiments.The results demonstrate that the proposed robust model can effectively reduce the risk of the UAV failing to return to the depot without significantly compromising the profit.
基金supported by the National Natural Science Foundation of China (Grant Nos.U20A20168 and 62404120)the National Key R&D Program (Grant No.2022YFB3204100)+2 种基金the Postdoctoral Fellowship Program of CPSF (Grant Nos.GZB20240335 and GZC20231216)the China Postdoctoral Science Foundation (Grant No.2025T180151)the Initiative Scientific Research Program of the School of Integrated Circuits,Tsinghua University。
文摘Block copolymer(BCP) nanolithography offers potential beyond traditional photolithographic limits, yet reliably producing low-defect, perpendicular domains remains challenging. We introduce a microenvironmentdriven isothermal annealing method for directed self-assembly of BCP thin films. By annealing films at stable temperature in a quasi-sealed, inert-gas chamber, our approach promotes highly uniform perpendicular lamellar nanopatterns over large areas, effectively mitigating environmental fluctuations and emulating solvent-vapor annealing without solvent exposure. Resulting BCP structures demonstrate enhanced spatial coherence and notably low defect density. Furthermore, we successfully transfer these nanopatterns into precise metal nano-line arrays,confirming the method's capability for high-fidelity pattern replication. This scalable, solvent-free technique provides a robust, reliable route for high-resolution nanopatterning in advanced semiconductor manufacturing.
基金supported by the Fundamental Research Funds for the Central Universities(No.2019ZDPY04).
文摘In this work,the TiO_(2)/Sb_(2)S_(3) nanorod arrays(NRAs)were synthesized through a two-stage hydrothermal route for photoelectrochemical(PEC)water splitting.The effect of annealing treatment in Ar ambience on the PEC activity of TiO_(2)/Sb_(2)S_(3) composite sample was investigated by electrochemical impedance analysis,including Nyquist and Mott-Schottky(M-S)plots.It was demonstrated that vacuum annealing could crystallize Sb_(2)S_(3) component and change its color from red to black,leading to an increment of photocurrent density from 1.9 A/m^(2) to 4.25 A/m^(2) at 0 V versus saturated calomel electrode(VSCE).The enhanced PEC performance was mainly attributed to the improved visible light absorption.Moreover,annealing treatment facilitated retarding the electron-hole recombination occurred at the solid/liquid interfaces.Our work might provide a novel strategy for enhancing the PEC performance of a semiconductor electrode.
基金Key Research and Development Plan of Shaanxi Province(2023-YBGY-493)。
文摘As-forged WSTi6421 titanium alloy billet afterβannealing was investigated.Abnormally coarse grains larger than adjacent grains could be observed in the microstructures,forming abnormal grain structures with uneven size distribution.Through electron backscattered diffraction(EBSD),the forged microstructure at various locations of as-forged WSTi6421 titanium alloy billet was analyzed,revealing that the strength of theβphase cubic texture generated by forging significantly influences the grain size afterβannealing.Heat treatment experiments were conducted within the temperature range from T_(β)−50°C to T_(β)+10°C to observe the macro-and micro-morphologies.Results show that the cubic texture ofβphase caused by forging impacts the texture of the secondaryαphase,which subsequently influences theβphase formed during the post-βannealing process.Moreover,the pinning effect of the residual primaryαphase plays a crucial role in the growth ofβgrains during theβannealing process.EBSD analysis results suggest that the strength ofβphase with cubic texture formed during forging process impacts the orientation distribution differences ofβgrains afterβannealing.Additionally,the development of grains with large orientations within the cubic texture shows a certain degree of selectivity duringβannealing,which is affected by various factors,including the pinning effect of the primaryαphase,the strength of the matrix cubic texture,and the orientation relationship betweenβgrain and matrix.Comprehensively,the stronger the texture in a certain region,the less likely the large misoriented grains suffering secondary growth,thereby aggregating the difference in microstructure and grain orientation distribution across different regions afterβannealing.
基金supported by the National Natural Science Foundation of China(No.52001106)Hebei province(No.E2022202158).
文摘Pre-stretching and annealing treatments were conducted on twin roll cast Mg-2Al-1Zn-1Ca(AZX211,in wt.%)plates with a rare earth-like texture.Varying amounts of deformation were applied along the rolling direction(RD)and transverse direction(TD)of AZX211 alloy in order to modify its mechanical proper-ties at room temperature.The results demonstrate that pre-stretching treatment effectively enhances the yield strength(YS),especially along the RD.The strengthening mechanism is attributed to the production of a large number of dislocations and sub-grain boundaries,but the work-hardening ability of the plate will be greatly weakened.Additionally,annealing treatment substantially improves the plasticity and in-plane anisotropy and restores the work-hardening ability.The notable distinction in the pre-stretching process between different directions lies in the underlying deformation mechanism.In case of RD,de-formation is predominantly governed by the slip mechanism of{0002}{11−20}basal slip and{10−10}{11−20}prismatic slip,while along the TD,deformation is primarily controlled by{0002}{11−20}basal slip without significant twinning deformation.When a 6%pre-stretching is conducted,the initial rare earth-like texture of the sample transforms into a symmetrically distributed double-peak basal texture,accompanied by grain refinement.This texture transformation is chiefly due to the dominance of{0002}{11−20}basal slip-driven deformation.Moreover,the annealed sample maintains a strong basal texture,owing to strain-induced recrystallization.
文摘The effect of hot band annealing processes—batch annealing and continuous annealing—on the texture evolution and ridging performance of ferritic stainless steel was investigated.The surface and central layers of the hot band exhibited strong shear and plane deformation textures,respectively.After batch annealing,the texture intensity of the hot-rolled sheet texture significantly decreased,and a weak recrystallization texture appeared,while fully recrystallized grains occurred after continuous annealing.A complete recrystallized{111}texture was obtained after recrystallization annealing.The sheet subjected to continuous annealing exhibited the highest intensity of{111}texture,which was accompanied by a dispersed grain orientation distribution,resulting in the lowest ridging height.
基金Research Foundation of Shenyang National Laboratory for Materials Science(L2019F15)Ling Chuang Research Project of China National Nuclear Corporation(CNNC-LCKY-202279)。
文摘The microstructures and corrosion behavior of 1.0wt%Gd-containing neutron-absorbing duplex stainless steel annealed at different temperatures were studied.Results reveal that the content of Gd-containing secondary phase increases with increasing the annealing temperatures to 1080℃,and then decreases.In the sample annealed at 1080℃,M-Gd(M=Fe,Cr,Ni)intermetallic with M_(3)Gd as the core phase and M_(12)Gd as the shell is the primary secondary phase.In the sample annealed at 1140℃,M_(3)Gd phase is dominant.The corrosion behavior of the two annealed steel samples were analyzed in NaCl,HCl and H_(3)BO_(3) solutions.It is found that the sample annealed at 1140℃ has lower corrosion rate.M_(3)Gd is more electrochemically active than M_(12)Gd when the sample is immersed in NaCl and HCl solutions,but more noble in H_(3)BO_(3) solution.
基金Project supported by the Major Special Project of Fujian Province(2023HZ021005)the Guiding Project of Fujian Province(2023H0006)+2 种基金the Major Project of Science and Technology of Fuzhou(2022-ZD-010)the Young and Middle-aged Teachers Education Scientific Research Project of Fujian Province(JAT200594,JAT231008)the Natural Science Foundation of Fujian Province(2022J011151)。
文摘In this work,the properties and microstructure of sintered Nd-Pr-Fe-Co-Zr-Ga-Cu-B magnet prepared by the single-step annealing,double-step annealing,and triple-step annealing processes were studied.The triple-step annealed magnet exhibits the highest intrinsic coercivity of 19.72 kOe,which is a 58.5%enhancement relative to the as-sintered magnet,and has the best temperature stability of coercivity.The best continuity of grain boundary(GB)phase and the highest content of RE6Fe13Ga phase can be observed in the triple-step annealed magnet,along with relatively small grain size.After triple-step annealing process,the phase separation occurs at the triple-junction(TJ)region of the magnet,which is the Fe-rich phase identified as RE6Fe13Ga and the Fe-poor phase identified as Ia-RE_(2)O_(3).The Ia-RE_(2)O_(3)phase located at the corner of the TJ region can extend between the grains of(Nd,Pr)_(2)Fe_(14)B main phase to form the GB phase with a Fe content of less than 15 at%,thereby enhancing the magnetic isolation effect.The lattice misfit between the Ia-RE_(2)O_(3)phase and the adjacent main phase is less than 5%,which is helpful to reduce defects at the edges of the main phase grains,thus reducing the nucleation of reverse domains.
基金financially supported by the Cultivation Project of CQUT for Research and Innovation Group(No.2023TDZ006)the Graduate Student Innovation Program of CQUT(No.CYS23648)the Postdoctoral Science Foundation of China(No.2021M690174)。
文摘A high-purity Ti sheet with dense preexisting twins(introduced by 10%cold rolling)was subjected to isochronal annealing at 500–800°C for 1 h and isothermal annealing at 600°C for 0.17–100 h,respectively.By mainly utilizing electron backscatter diffraction(EBSD)and electron channel contrast(ECC)imaging techniques,the microstructure and texture evolution during the isochronal and isothermal annealing were investigated systematically.Results show that recrystallization nuclei appear in the specimen annealed at 600°C for 1 h.In contrast,recrystallization cannot be initiated for those annealed at lower temperatures or for a shorter time.With the increase in temperature or time,the fraction of the recrystallized structure increases with gradual grain coarsening.Nearly complete recrystallization is reached after 800°C-1 h or 600°C-100 h annealing.Due to the distribution heterogeneity of microstructure and stored energy induced by the dense preexisting twins,recrystallization nucleation preferentially occurs in some specific regions(twin-twin or twin-grain boundary junctions).Then,they selectively consume twin lamellar structures,leading to non-uniform grain growth.It is demonstrated that the recrystallization nucleation is dominated by the strain-induced boundary migration mechanism,allowing scattered texture components corresponding to the twin lamellar structures to be gradually encroached by those untwinned structures with the initial bimodal basal texture(BBT).Eventually,a strong BBT is always obtained after sufficient recrystallization.
基金supported by the National Natural Science Foundation of China(Grant Nos.52075385 and 12034001)the National Key R&D Program(Grant No.2018YFA0307200)the 111 Project(Grant No.B07014).
文摘Two-dimensional transition metal dichalcogenides(TMDs)show great promise for developing the next generation of electronic and optoelectronic devices.However,most TMDs have n-type or n-dominant bipolar characteristics,and this severely limits their potential for being designed as multi-functional heterostructures.Recently,thermal annealing has been reported as an easy means of p-doping TMDs,but the mechanism remains ambiguous,thereby preventing reliable outcomes and it becoming a mature doping technology for TMDs.Here,the mechanism of thermal annealing for p-doping a 2D selenide is investigated thoroughly,revealing the key role of the catalytic effect of nano-thick gold electrodes in achieving p-doping.As an example,2D SnSe_(2)with a fairly high electron density of∼10^(18)cm^(−3)is used,and its electrical performance is greatly enhanced after thermal annealing when 30-nm-thick gold electrodes are deposited.The results of performing XPS and Auger electron spectroscopy on samples before and after annealing show that the p-doping effect is due to the oxidation of selenide atoms,during which the gold acts as a critical catalytic element.This method is also shown to be valid for other 2D selenides including WSe_(2)and MoSe_(2),and the present findings offer new avenues for enriching the electrical properties of 2D selenides by means of annealing.
基金supported by the National Natural Science Foundation of China(No.52071012)Open Research Fund of the National Key Laboratory of Advanced Casting Technologies(No.CAT2023-004)+2 种基金Key Research and Development Program of Shandong Province,China(No.2022JMRH0209)Hebei Province Innovation Capability Enhancement Plan Project,China(No.244A7607D)the Open Foundation of the State Key Laboratory for Advanced Metals and Materials(No.2022-Z01).
文摘A series of as-cast Si_(x)Al_(0.43)CoCrFeNi_(2.1)(x=0,0.1,0.2,and 0.3)high-entropy alloys(HEAs)was successfully fabricated by va-cuum-assisted melting.The phase constituents,microstructural features,and mechanical properties(including hardness,tensile behavior,and wear behavior)of alloys with various Si contents were evaluated.The results revealed that the addition of Si promoted the precipita-tion of a body-centered cubic 1(BCC1)phase enriched in Al,Ni,and Si with a B2-ordered structure.Furthermore,the secondary BCC2 phase was enriched with Cr,Fe,and Si precipitates within the BCC1 matrix.Ultimately,a multiphase face-centered cubic(FCC)/(BCC1/BCC2)structure was formed.The microstructural evolution driven by Si addition significantly enhanced the mechanical properties of the Si_(x)Al_(0.43)CoCrFeNi_(2.1) HEAs.As the Si content increased,the microhardness and tensile strength improved by approxim-ately 42%and 55%,reaching 2.359 GPa and 785 MPa,respectively.The quantitative evaluation of the various strengthening mechanisms indicated that the intrinsic hardness of the FCC matrix and hardening due to BCC1/BCC2 precipitation dominated the overall microhard-ness.The comparison of the energy barriers indicates that BCC2 primarily strengthens the alloy through a shear mechanism rather than an Orowan bypass mechanism.Furthermore,with increasing Si content,reduced friction and wear,together with smoother worn surfaces,re-flect a greatly enhanced wear resistance.After the optimal cold-rolling and 1 h annealing at 800℃,the Si_(0.3)Al_(0.43)CoCrFeNi_(2.1) alloy showed 56%and 62%increases in microhardness and tensile strength,respectively,compared to the as-cast state,reaching 3.68 GPa and 1270 MPa.The enhanced mechanical properties are attributed to the synergistic effects of residual strain hardening by FCC ordering and L1_(2)/BCC precipitation strengthening.
基金supported by National Key R&D Program of China(Grant No.2022YFB4601701)74th Batch of General Funding from the China Postdoctoral Science Foundation(Grant No.2023M741341)+7 种基金5th Batch of Special Grants from the China Postdoctoral Science Foundation(before the station,Grant No.2023TQ0129)Postdoctoral Fellowship Program of CPSF(Grant No.GZB20230257)National Natural Science Foundation of China(Grant Nos.52375289,52205310)Natural Science Foundation of Shandong Province(Grant No.ZR2021QE263)Science and Technology Development Program of Jilin Province(Grant No.20230508045RC)Capital Construction Fund plan within the budget of Jilin Province(Grant No.2023C041-4)Chongqing Natural Science Foundation(Grant No.CSTB2022NSCQ-MSX0225)the Shandong Postdoctoral Science Foundation(Grant No.SDCX-ZG-202400238).
文摘The emergence of additive manufacturing technology,particularly laser powder bed fusion,has revitalized NiTi alloy production.However,challenges arise regarding its mechanical properties and diminishing shape memory effect,which hinder its widespread application.Heat treatment has been identified as a method to enhance the performance of metallic materials in the realm of additive manufacturing.This process eliminates residual stress and enhances performance through precipitation strengthening.This study conducted a comprehensive annealing investigation on NiTi alloys to explore the impact of annealing time and temperature on the phase transformation behavior and shape memory performance.The mechanism underlying the performance enhancement was analyzed using scanning electron microscopy,energy-dispersive X-ray spectroscopy,electron backscatter diffraction,and transmission electron microscopy.The findings revealed that different annealing conditions resulted in multistep phase transformation behavior,with the 500℃-5 h sample exhibiting the best mechanical properties owing to the formation of nanoscale dispersed precipitates like Ni_(4)Ti_(3).However,higher temperatures led to larger precipitates,significantly weakening the properties of the NiTi alloy.Additionally,the annealing treatment did not have a notable impact on the grain size,texture strength,or direction.This study provides valuable insights for optimizing the heat treatment process of LPBF-NiTi alloys.
基金supported by the Sichuan Provincial Regional Innovation Cooperation Project(No.2024YFHZ0159).
文摘Semicrystalline polymers usually undergo multilevel microstructural evolutions with annealing and stretching processes,which is es-sential to tailor the physical properties of the polymer.Here,poly(butylene carbonate)(PBC)sheets were prepared via isothermal annealing and unidirectional pre-stretching processes,then the changes of PBC in crystallinity,mechanical properties,thermal properties and microscopic changes before and after annealing and stretching were measured,as well as the relationship between microstructure and macroscopic proper-ties before and after stretching.The strengthening mechanism of PBC was also described.It was demonstrated that shish-kabab structure emerged under the pre-stretching process.With the increase of the tensile ratio,the crystallinity,structure and mechanical properties are in-creased differently.Among them,the crystallinity and tensile strength after annealing-stretching treatment increased to 24.45%and 104.5 MPa,respectively,which were about 1.55 times and 3.4 times of those-without any treatment.
基金support from the National Natural Science Foundation of China(No.52271146)New 20 Items of Colleges and Universities in Jinan,China(No.202228111)University of Jinan Disciplinary Cross-Convergence Construction Project 2023,China(No.XKJC-202311).
文摘The effect of cryogenic treatment(CT)and relaxation annealing on the average nearest neighboring distance of atom(dm),ther-modynamic stability,soft magnetic properties,microhardness(Hv),and corrosion resistance of as-spun(Fe_(0.5)Co_(0.5))_(75)B_(21)Nb_(4) metallic glasses(MGs)is studied.On the premise of maintaining a fully amorphous phase,appropriate CT and relaxation annealing are conducive to achieving the synergistic effect of increasing saturation magnetization(M_(s))and reducing coercivity(H_(c)).Shallow CT at 213 K optim-ally enhances the soft magnetic properties of MGs.Given its low activation energy of nucleation and increased activation energy of growth,appropriate CT is beneficial for achieving uniform annealed nanocrystals in amorphous phases.The correlation between free volumes(FVs)and potential energy suggests that the variation in Hc depends on the expansion and contraction behavior of amorphous phases after different CT processes.The fitting formulas of H_(c)–d_(m) and Ms–Hv correlations demonstrate that soft magnetic parameters have a solid linear relationship with the contents of FVs and degree of dense random packing.Moreover,pitting resistance is improved by ap-propriate CT and relaxation annealing.This improvement is characterized by the promotion of the stability of the Nb-rich passive film formed during electrochemical corrosion in 3.5wt%NaCl solution.
基金supported by the National Key R&D Program of China(No.2021YFE0100600)the National Natural Science Foundation of China(No.52371154)+2 种基金Guangdong Basic and Applied Basic Research Foundation(No.2023A1515012158)the Opening Project of the Key Laboratory of CNC Equipment Reliability,Ministry of Education,Jilin University(No.JLU-cncr-202307)the Knowledge Innovation Program of Wuhan-Basic Research(No.2022010801010087).
文摘This study comprehensively investigates the effects of annealing on the structural,electrochemical properties and passivation film characteristics of Ti_(20)Zr_(20)Hf_(20)Be_(20)Ni_(20)(at%)high-entropy metallic glass(HE-MG).Subjected to various annealing temperatures,the samples were analyzed in a 3.5 wt%NaCl solution to evaluate changes in their microstructure and assess their corrosion resistance.Findings reveal that the HE-MG undergoes multistage crystallization,displaying an amorphous matrix integrated with face centered cubic(FCC)and Ni_(7)Zr_(2)phases between 420 and 500℃,indicating robust thermal stability.Electrochemical assessments identify a critical temperature threshold:Below the glass transition temperature(Tg),the HE-MG maintains excellent corrosion resistance,promoting stable passivation layers.Above Tg,enhanced long-range atomic rearrangement during relaxation increases passivation layer defects and significantly diminishes corrosion resistance.X-ray photoelectron spectroscopy(XPS)analyses show that the primary components of the passivation layer are TiO_(2),ZrO_(2),HfO_(2)and BeO.Increased annealing temperatures lead to enhanced Be and Ni content and decreased Ti,Zr and Hf.Additionally,high mixing entropy and significant atomic size mismatch suppress long-range atomic rearrangement and crystallization.The crystallization begins above Tg by_(20)℃,with crystalline phases evenly distributed within the matrix without drastically affecting corrosion resistance.This investigation highlights the impact of thermal treatment on the properties of HE-MG,contributing valuable insights into optimizing their performance and applications.
基金support from the National Natural Science Foundation of China(Grant No.52174359)is greatly acknowledged.
文摘Twinning-induced plasticity (TWIP) steel shows great potential in engineering due to its excellent strength and ductility synergy, and strengthening research on its corrosion resistance and high-temperature oxidation resistance is critical for broader applications. Herein, the effect of annealing temperature on the high-temperature oxidation and corrosion behavior of Fe-Mn-Cr-Al-Cu-C TWIP steel is investigated. The results show that increasing the annealing temperature from 700℃ to 1100℃ reduced the mass gain of the TWIP steel oxidized at 800℃ for 8 h from 1.93 to 0.58 mg·cm^(−2). Additionally, the self-corrosion current density decreases from 6.52 × 10^(−6) to 1.32 × 10^(−6) A·cm^(−2), while charge transfer resistance increases from 1461 to 3339 Ω·cm^(−2). The reduction in grain boundaries and dislocation density in the TWIP steel attributed to the increase in annealing temperature inhibits short-circuit diffusion, local galvanic corrosion and pitting, ultimately improving both oxidation and corrosion resistance. Moreover, high-temperature annealing prevents the formation of carbon-rich compounds and ensures uniform element distribution. The accumulation of Cu and Cu-rich products formed at the interface further protects against Cl− erosion, inhibiting pitting and local corrosion, thus enhancing the corrosion resistance of the TWIP steel.
