Microstructural characterization,mass loss tests,hydrogen evolution tests,electrochemical measurements,and corrosion morphology observations were conducted to investigate the effect of the secondary phases on the corr...Microstructural characterization,mass loss tests,hydrogen evolution tests,electrochemical measurements,and corrosion morphology observations were conducted to investigate the effect of the secondary phases on the corrosion behavior of the as-cast Mg−7Sn−1Zn−1Y(TZW711)alloy after solution treatment(T4)and aging treatment(T6).The results show that the T4-TZW711 alloy possesses the highest corrosion resistance in the early corrosion stage.This is because the dissolution of Mg2Sn reduces the cathodic current density and increases the charge transfer resistance(Rct).When the corrosion time is prolonged,the undissolved and clustered MgSnY phase will peel off from the T4-TZW711 alloy surface,thereby increasing the corrosion rate of the alloy.After aging treatment,the undissolved MgSnY phase is dispersed,which results in a lower localized corrosion sensitivity of T6-TZW711 alloy than that of the T4-TZW711 alloy,suggesting that the T6 treatment can enhance the corrosion resistance of Mg−7Sn−1Zn−1Y alloys.展开更多
As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.Thi...As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.This work establishes a dynamic behavior model of steel catenary risers(SCRs)with varying curvatures subjected to internal flow and external currents and considers the effects of pipe-soil interactions on the curvature profile.The governing equation is solved via the generalized integral transform technique(GITT),which yields a semi-analytical solution of a high-order nonlinear partial differential equation.Parametric studies are then performed to analyze the effects of varying curvature on the vibration frequency and amplitude of SCRs.The vibration frequency and amplitude increase with the touchdown angle and hang-off angle,although the effect of the hang-off angle is negligible.Additionally,as the curvature increases along the centerline axis,the position of the maximum amplitude of the SCR moves upward.展开更多
Al-Cu-Mn alloys are widely used to produce automobile components like cylinder heads and engine blocks because of their capability to retain excellent thermal and mechanical characteristics at high temperatures.Howeve...Al-Cu-Mn alloys are widely used to produce automobile components like cylinder heads and engine blocks because of their capability to retain excellent thermal and mechanical characteristics at high temperatures.However,the Al-Cu-Mn-based alloys demonstrate restricted fluidity,leading to casting defects such as shrinkage and incomplete filling.This research investigated the microstructure and fluidity of Al-4.7Cu-1.0Mn-0.5Mg(wt%)alloy with minor cerium(Ce)addition.The as-cast alloys predominantly compriseα-Al matrix,accompanied by the presence of Al_(2)Cu,Al_(6)Mn,and Al_(8)Cu_(4)Ce phases.The influence of adding Ce on the fluidity of the Al-4.7Cu-1.0Mn-0.5Mg alloy was investigated using a trispiral fluidity test mold in this research.The findings suggest that the addition of Ce within the range of 0.1 wt%to 0.5 wt%in the Al-4.7Cu-1.0Mn-0.5Mg alloy results in an enhancement in fluidity.Specifically,the alloy containing 0.4 wt%Ce exhibits a significant increase in fluidity distance,from 349.7 to 485.7 mm.This improvement can be attributed to the reduction in viscosity,the refinement of secondary dendrite arm spacing,and the modification of secondary phase particles.However,a higher concentration of Ce leads to a decrease in fluidity length,potentially due to the formation of Al_(8)Cu_(4)Ce.展开更多
Ferroptosis is a novel form of cell death driven by oxidative damage,and is implicated in various pathological conditions,including neurodegenerative diseases,retinal damage,and ischemia-reperfusion injury of organs.I...Ferroptosis is a novel form of cell death driven by oxidative damage,and is implicated in various pathological conditions,including neurodegenerative diseases,retinal damage,and ischemia-reperfusion injury of organs.Inhibiting ferroptosis has shown great promise as a therapeutic strategy for these diseases,underscoring the urgent need to develop effective ferroptosis inhibitors.Although Ferrostatin-1(Fer-1)is a potent ferroptosis inhibitor,its susceptibility to oxidation and metabolic inactivation limits its clinical utility.In this study,the accumulation of peroxides and the resulting oxidative damage in the cellular microenvironment during ferroptosis were utilized to design Ferrostatin-1 prodrugs with reactive oxygen species-responsive features.This approach led to the development of a series of ferroptosis inhibitors that were capable of recognizing oxidative damage in diseased areas,allowing for targeted release and improved stability.The novel compounds demonstrated significant inhibitory effects and selectivity against RSL-3-induced ferroptosis in HK-2 cells,with compound a1 exhibiting an EC50 of 15.4�0.7μM,outperforming Fer-1.These compounds effectively identify the oxidative microenvironment associated with ferroptosis,enabling the targeted release of Fer-1,which prevents lipid peroxide accumulation and inhibits ferroptosis.This strategy holds promise for treating diseases related to ferroptosis,offering a targeted and intelligent therapeutic approach.展开更多
The carcass layer is the innermost structure of flexible marine risers and is responsible for resisting external pressure.It has an“S”section with a spiral interlocking feature.After the multi-pass roll forming of a...The carcass layer is the innermost structure of flexible marine risers and is responsible for resisting external pressure.It has an“S”section with a spiral interlocking feature.After the multi-pass roll forming of a flat steel strip,a carcass layer is formed by lock forming.During roll forming,the steel strip undergoes significant plastic deformation,and its local area accumulates residual stress owing to multiple loading and unloading cycles.These phenomena complicate the design and analysis of the carcass layer multi-pass roll forming(CLMRF)process and cause issues in the carcass layer during manufacturing,such as strip fracture and low forming quality.Thus,herein,CLMRF was investigated to clarify the stress distribution,and a parameter analysis was performed.First,the CLMRF process was designed on the basis of classical roll-forming design theory.Second,a finite element model was established,and CLMRF was simulated.Third,the distributions of the forming stress and residual stress of the strip during CLMRF were investigated.Finally,the influences of the strip thickness,roll gap,roll distance,and angular increment were investigated.The conclusions of this study can be used to provide technical guidance in the manufacturing of flexible risers.展开更多
Phosphor bronze is a commonly used elastic copper alloy,widely applied in electronic connectors and terminals[1-4].With the rapid development of 5 G mobile communication technology and the new energy vehicle industry,...Phosphor bronze is a commonly used elastic copper alloy,widely applied in electronic connectors and terminals[1-4].With the rapid development of 5 G mobile communication technology and the new energy vehicle industry,the size requirements for connectors have been reduced,while the demand for strength has gradually increased[5].This requires the alloy to possess higher strength and better deformability.展开更多
Mitochondria are crucial organelles responsible for maintaining cell growth,and their homeostasis is closely linked to p H regulation.Physiologically,mitochondria exhibit a weakly alkaline state(pH~8.0).However,when s...Mitochondria are crucial organelles responsible for maintaining cell growth,and their homeostasis is closely linked to p H regulation.Physiologically,mitochondria exhibit a weakly alkaline state(pH~8.0).However,when subjected to stress stimuli that cause damage,cells initiate the process of mitophagy,resulting in mitochondrial acidification.Therefore,monitoring changes in mitochondrial p H to comprehend the physiological processes associated with mitophagy is essential.In this study,we developed an asymmetric pentamethine cyanine dye Cy5.5-H-Cy N as a probe for continuous monitoring of mitophagy in living cells.By incorporating an azaindole structure into the dye molecule,a ratiometric fluorescence response was achieved that is specifically responsive to p H variations while preserving its ability to target mitochondria and emit near-infrared fluorescence.Through various methods inducing mitophagy,Cy5.5-H-Cy N was employed to determine mitochondrial p H quantitatively,demonstrating its suitability as an ideal probe for continuous monitoring of mitophagy in living cells.展开更多
The Cu/1010 steel bimetal laminated composites(BLCs)were rolled to different thicknesses to investigate the effect of rolling direction and reduction on the microstructure evolution and mechanical properties.The diffe...The Cu/1010 steel bimetal laminated composites(BLCs)were rolled to different thicknesses to investigate the effect of rolling direction and reduction on the microstructure evolution and mechanical properties.The difference of mechanical properties between the Cu and 1010 steel causes different thickness reductions,percentage spread,and cladding ratios.The formation of strong texture induces larger strength of the rolled samples,and as the volume fraction of 1010 steel is larger in Route-A,its strength is consistently greater than that in Route-B.The obstruction of interface to crystal and dislocation slip results in the formation of interface distortion,inducing dislocation density gradient when the rolling reduction is low in Route-A.The slip planes of the Cu and 1010 steel are more prone to suffer the normal strain,while the shear strain of other crystal planes is obviously larger than the normal strain under rolling load near the interface.展开更多
To optimize the comprehensive properties of Ni−Si precipitation strengthened phosphor bronze,the impact of the Ni/Si mass ratio and heat treatment process on a Cu−8Sn−0.1P−1Ni−xSi alloy was explored.High resolution fi...To optimize the comprehensive properties of Ni−Si precipitation strengthened phosphor bronze,the impact of the Ni/Si mass ratio and heat treatment process on a Cu−8Sn−0.1P−1Ni−xSi alloy was explored.High resolution field emission scanning electron microscopy and transmission electron microscopy were used for microstructural characterization.The results indicate that the properties are influenced by the Ni/Si mass ratio,attributed to the formation of various second phases.Simultaneously,by influencing the diffusion rate,the microstructures and properties are influenced by the solid solution treatment.The strength is enhanced by precipitated nanoscale particles during the aging process by influencing the motion of dislocations.Ultimately,excellent comprehensive properties,including ultimate tensile strength,yield strength,and elongation of 866 MPa,772 MPa,and 8.7%,respectively,are obtained in the Cu−8Sn−0.1P−1Ni−0.227Si alloy.展开更多
In this work,the microstructure evolution and mechanical behavior of extruded SiC/ZA63 Mg matrix composites are investigated via combined experimental study and three-dimensionalfinite element modelling(3D FEM)based on...In this work,the microstructure evolution and mechanical behavior of extruded SiC/ZA63 Mg matrix composites are investigated via combined experimental study and three-dimensionalfinite element modelling(3D FEM)based on the actual 3D microstructure achieved by synchrotron tomography.The results show that the average grain size of composite increases from 0.57μm of 8μm-SiC/ZA63 to 8.73μm of 50μm-SiC/ZA63.The type of texture transforms from the typicalfiber texture in 8μm-SiC/ZA63 to intense basal texture in 50μm-SiC/ZA63 composite and the intensity of texture increases sharply with increase of SiC particle size.The dynamic recrystallization(DRX)mechanism is also changed with increasing SiC particle size.Experimental and simulation results verify that the strength and elongation both decrease with increase of SiC particle size.The 8μm-SiC/ZA63 composite possesses the optimal mechanical property with yield strength(YS)of 383 MPa,ultimate tensile strength(UTS)of 424 MPa and elongation of 6.3%.The outstanding mechanical property is attributed to the ultrafine grain size,high-density precipitates and dislocation,good loading transfer effect and the interface bonding between SiC and matrix,as well as the weakened basal texture.The simulation results reveal that the micro-cracks tend to initiate at the interface between SiC and matrix,and then propagate along the interface between particle and Mg matrix or at the high strain and stress regions,and further connect with other micro-cracks.The main fracture mechanism in 8μm-SiC/ZA63 composite is ductile damage of matrix and interfacial debonding.With the increase of particle size,interface strength and particle strength decrease,and interface debonding and particle rupture become the main fracture mechanism in the 30μm-and 50μm-SiC/ZA63 composites.展开更多
This study constructed an in vitro blood-brain barrier(BBB)transwell model to investigate the regulatory effects and mechanisms of the photothermal effects of gold nanorods(AuNRs)excited by the second near-infrared re...This study constructed an in vitro blood-brain barrier(BBB)transwell model to investigate the regulatory effects and mechanisms of the photothermal effects of gold nanorods(AuNRs)excited by the second near-infrared region(NIR-II)on BBB permeability.The experimental results showed that the photothermal effects of NIR-II t AuNRs significantly decreased trans-epithelial electrical resistance(TEER)and increased the permeability of fluorescein isothiocyanate(FITC)-dextran,indicating that it can effectively open the BBB.This effect was reversible,and the TEER and FITC permeability returned to baseline levels within 24 h after treatment.Mechanistic studies revealed that BBB opening did not rely on apoptosis,cytoskeletal disruption,mitochondrial dysfunction,or inflammation.The opening of the BBB was closely associated with a temporary decrease in the expression and conformational change of the tight junction protein occludin due to the photothermal effect.Molecular simulations and docking analysis revealed that the heat shock protein HSP70 could bind to the conformationally altered occludin,supporting the regulatory role of photothermal effects on tight junction proteins.In summary,NIR-II t AuNRs achieved safe and reversible opening of the BBB by regulating the conformation and expression of tight junction proteins,providing a deeper insight for further research on BBB and the treatment of neurological diseases.展开更多
Different from full-Heusler compounds,four vacancies in the face-centered cubic crystal structure provide extra sites for enhancing the thermoelectric properties of half-Heusler compounds(HHs).Herein,excess Ag is intr...Different from full-Heusler compounds,four vacancies in the face-centered cubic crystal structure provide extra sites for enhancing the thermoelectric properties of half-Heusler compounds(HHs).Herein,excess Ag is introduced to the Ni-site vacancies of ZrNiSn to optimize thermoelectric properties.The ZrNiAg_(x)Sn(x=0,0.01,0.02,and 0.03)samples were synthesized by levitation melting and spark plasma sintering.Remarkably,the introduction of excess Ag significantly improves the Seebeck coefficient of ZrNiAg_(0.01)Sn,and a peak power factor of~4.52 mW/(m K^(2))is achieved in ZrNiAg_(0.01)Sn at 923 K,which is enhanced by 22.8%than that of pristine ZrNiSn.As a result,the figure of merit zT of pristine ZrNiSn is enhanced from~0.60 to~0.72 of ZrNiAg_(0.01)Sn at 923 K.Additionally,grain refinement effectively increases the Vickers hardness of ZrNiAg_(0.01)Sn,which is enhanced by 32.8%than that of pristine ZrNiSn.These results demonstrate a viable doping strategy for designing ZrNiSn-based HHs with excellent thermoelectric and mechanical properties.展开更多
This study develops novel Mg-Sn-In-Ga alloys as potential implant materials for orthopedic applications.The corrosion behavior of the Mg-Sn-In-Ga alloys was studied through mass loss measurements,hydrogen evolution me...This study develops novel Mg-Sn-In-Ga alloys as potential implant materials for orthopedic applications.The corrosion behavior of the Mg-Sn-In-Ga alloys was studied through mass loss measurements,hydrogen evolution measurements,electrochemical analysis,and corrosion morphology observations.The results show that the corrosion rate of the Mg-1Sn-1In-1Ga alloy was only 0.10±0.003 mm/y after immersion in Hank’s solution for 15 days.This outstanding corrosion resistance was associated with the protective efect of the corrosion products.The increase in the Sn and Ga element content led to the precipitation of a large amount of Mg_(2)Sn and Mg_(5)Ga_(2),which had a dominant efect on the corrosion rate in the Mg-5Sn-1In-2Ga alloy.These precipitates increased the current density and detached from the alloy surface during the corrosion process.This can lead to a weakened protective efect of the corrosion layer,and thus generate localized corrosion and an increase in the corrosion rate.The strength of the Mg-5Sn-1In-2Ga alloy was enhanced due to fne-grain strengthening and precipitation strengthening.The ultimate tensile strength and yield strength of the Mg-5Sn-1In-2Ga alloy were~309 MPa and~253 MPa,respectively.展开更多
G protein coupled receptor kinase 2 (GRK2) is a kinase that regulates cardiac signaling activity. Inhibiting GRK2 is a promising mechanism for the treatment of heart failure (HF). Further development and optimization ...G protein coupled receptor kinase 2 (GRK2) is a kinase that regulates cardiac signaling activity. Inhibiting GRK2 is a promising mechanism for the treatment of heart failure (HF). Further development and optimization of inhibitors targeting GRK2 are highly meaningful. Therefore, in order to design GRK2 inhibitors with better performance, the most active molecule was selected as a reference compound from a data set containing 4-pyridylhydrazone derivatives and triazole derivatives, and its scaffold was extracted as the initial scaffold. Then, a powerful optimization-based framework for de novo drug design, guided by binding affinity, was used to generate a virtual molecular library targeting GRK2. The binding affinity of each virtual compound in this dataset was predicted by our developed deep learning model, and the designed potential compound with high binding affinity was selected for molecular docking and molecular dynamics simulation. It was found that the designed potential molecule binds to the ATP site of GRK2, which consists of key amino acids including Arg199, Gly200, Phe202, Val205, Lys220, Met274 and Asp335. The scaffold of the molecule is stabilized mainly by H-bonding and hydrophobic contacts. Concurrently, the reference compound in the dataset was also simulated by docking. It was found that this molecule also binds to the ATP site of GRK2. In addition, its scaffold is stabilized mainly by H-bonding and π-cation stacking interactions with Lys220, as well as hydrophobic contacts. The above results show that the designed potential molecule has similar binding modes to the reference compound, supporting the effectiveness of our framework for activity-focused molecular design. Finally, we summarized the interaction characteristics of general GRK2 inhibitors and gained insight into their molecule-target binding mechanisms, thereby facilitating the expansion of lead to hit compound.展开更多
The development of a new generation of high-performance Al alloys,achieved through Sc/Zr-modified Al-Mg-based alloys,is attracting growing attention.However,the significant cost associated with Sc presents a barrier t...The development of a new generation of high-performance Al alloys,achieved through Sc/Zr-modified Al-Mg-based alloys,is attracting growing attention.However,the significant cost associated with Sc presents a barrier to further advancement.In this study,the inclusion of trace heterogeneous TiB_(2)particles is employed to regulate the microstructural evolution process,thereby achieving high-performance aluminum alloys with optimal strength-ductility characteristics with minimal Sc addition.The ultimate tensile strength of Al-Mg-Sc-Zr-TiB_(2)alloy reached 442.4 MPa,with a elongation of 16.6%.The combined impact of TiB_(2)particles and Al_(3)(Sc,Zr)precipitates on the microstructure evolution of the Al-Mg alloy during hot deformation was investigated.It was observed that spherical Al_(3)(Sc,Zr)precipitates with sizes ranging from 5 to 10 nm dispersed in the matrix,during the hot deformation process,functioned as Zener pinning sites for dislocations,thus increasing the proportion of low-angle grain boundaries(LAGBs)and suppressing the dynamic recrystallization(DRX)process.The incorporation of trace TiB_(2)particles induced the particle-stimulated nucleation effect,accelerating DRX and refining the microstructure.The density of LAGBs further increased,and the proportion of continuous dynamic recrystallization also rose.Furthermore,the TiB_(2)particles mitigated the anisotropy of material and inhibited DRX grain growth,thereby expanding the subsequent processing window and offering more potential applications for the materials.This study provides new insights into the production of high-performance Al alloy products.展开更多
In this study,a NbB_(2)/AZ91 composite exhibiting desirable mechanical properties was fabricated using a sample casting technique,followed by hard-plate rolling and short-term annealing.The effect of NbB_(2)particles ...In this study,a NbB_(2)/AZ91 composite exhibiting desirable mechanical properties was fabricated using a sample casting technique,followed by hard-plate rolling and short-term annealing.The effect of NbB_(2)particles on the microstructural evolution of the AZ91 alloy was investigated.The presence of NbB_(2)was shown to have a grain-refining effect on the AZ91 alloy and promoted dynamic recrystallization(DRX)and precipitation of fine Mg_(17)Al_(12)phases via particle-stimulated nucleation(PSN).Tensile testing revealed substantial enhancements in the ultimate tensile strength(UTS),yield strength(YS),and elongation(EL)of the as-rolled AZ91 alloy,with values of 379 MPa,292 MPa,and 14.7%,respectively,owing to the incorporation of NbB_(2)particles.Annealing led to further enhancements in EL with slight reductions in UTS and YS(360 MPa,252 MPa,and 16.8%,respectively).Owing to grain refinement and the PSN effect of the NbB_(2)particles,a significant number of geometrically necessary dislocations(GNDs)were induced in the matrix during the rolling process,which reduces the nucleation barrier and increases the number of nucleation sites for the recrystallized grains and Mg_(17)Al_(12)precipitates.Meanwhile,many residual dislocations and fine Mg_(17)Al_(12)precipitates in the as-rolled alloys were annihilated during annealing,resulting in slight grain growth and coarsening.The strengthening mechanism of the NbB_(2)/AZ91 composite are mainly associated with grain-refinement strengthening,particle-induced dislocation strengthening,strengthening resulting from mismatching coefficients of thermal expansion(CTE),and heterodeformation-induced(HDI)strengthening.Textural weakening,increased activation of non-basal slip systems,more-uniform strain patterns resulting from NbB_(2)particles,and precipitation are mainly responsible for enhancing ductility.展开更多
To evaluate the potential of high entropy alloys for marine applications,a new high entropy alloy coating of AlCrFeNiW_(0.2)Ti_(0.5)was designed and produced on Q235 steel via laser cladding.The microstructure,microha...To evaluate the potential of high entropy alloys for marine applications,a new high entropy alloy coating of AlCrFeNiW_(0.2)Ti_(0.5)was designed and produced on Q235 steel via laser cladding.The microstructure,microhardness and tribological performances sliding against YG6 cemented carbide,GCr15 steel and Si_(3)N_(4)ceramic in seawater were studied in detail.The AlCrFeNiW_(0.2)Ti_(0.5)coating showed an anomalous’sunflower-like’morphology and consisted of BCC and ordered B2 phases.The microhardness was approximately 692.5 HV,which was 5 times higher than substrate.The coating showed more excellent tribological performances than Q235 steel and SUS304,a typical material used in seawater environment,sliding against all three coupled balls in seawater.Besides,the wear and friction of AlCrFeNiW_(0.2)Ti_(0.5)coating sliding against YG6 in seawater were most mild.The main reason was the generation of Mg(OH)_(2),CaCO_(3),metal oxides and hydroxides and the formation of protective tribo-film on the worn surface of AlCrFeNiW_(0.2)Ti_(0.5)coating in the process of reciprocated sliding.This would effectively hinder the direct contact between the worn surfaces of AlCrFeNiW_(0.2)Ti_(0.5)coating and YG6 ball,resulting in a decrease of friction coefficient and wear rate.Thus the YG6 was an ideal coupled material for AlCrFeNiW_(0.2)Ti_(0.5)coating in seawater,and the coating would become a promising wear-resisting material in ocean environment.展开更多
In order to broaden the application of wrought Mg alloy sheets in the automotive industry,the influence of Ca and Sm alloying on the texture evolution,mechanical properties,and formability of a hot-rolled Mg-2Zn-0.2Mn...In order to broaden the application of wrought Mg alloy sheets in the automotive industry,the influence of Ca and Sm alloying on the texture evolution,mechanical properties,and formability of a hot-rolled Mg-2Zn-0.2Mn alloy was investigated by OM,XRD,SEM,EBSD,tensile tests,and Erichsen test.The results showed that the average grain size and basal texture intensity of Mg-2Zn-0.2Mn alloys were remarkably decreased after Ca and Sm additions.0.64 wt.%Ca or 0.48 wt.%Sm addition significantly increased the tensile strength,ductility and formability.Moreover,the synergetic addition of Sm and Ca improved the ductility and formability of Mg-2Zn-0.2Mn alloy,which was due to the change of Ca distribution and further reduction of the size of Ca-containing particles by Sm addition.The results provided a possibility of replacing RE elements with Ca and Sm in Mg alloys which bring about outstanding mechanical properties and formability.展开更多
The anti-bird-strike performance of a lattice-material-infilled curved plate is investigated herein.Since automatically filling the curved structure by classical lattice material filling methods will cause a large num...The anti-bird-strike performance of a lattice-material-infilled curved plate is investigated herein.Since automatically filling the curved structure by classical lattice material filling methods will cause a large number of manufacturing defects,a space-dependent lattice material filling method for the curved plate is firstly proposed in this paper Next,using a face-centered cubic lattice,a lattice-material-infilled test piece with a hollow ratio of 40.8%is built.The test pieces are manufactured via additive manufacturing using titanium alloy.In bird-strike experimental tests,the test pieces are crashed against gelatin birds at an impact velocity of 200 m/s.Dynamic strain gauges are used to record the crash history and the results are discussed.Furthermore,a numerical analysis to simulate the bird-strike experiment is performed.The results from the experimental tests and numerical simulation agree well.This work shows that the lattice-material-infilled curved plate yields promising bird-strike resistance.Therefore,lattice-infilled materials are feasible for protecting aerospace components against bird-strike as well as for reducing the component weight.展开更多
The microstructural observation,the mass loss test,potentiodynamic polarization measurements and corrosion morphology examinations were conducted to study the influence of microstructural characteristics on corrosion ...The microstructural observation,the mass loss test,potentiodynamic polarization measurements and corrosion morphology examinations were conducted to study the influence of microstructural characteristics on corrosion behavior of Mg–5Sn–3In alloys in Hank’s solution after extrusion.The results show that the corrosion rate of the as-cast alloy is similar to that of as-extruded alloy;however,the local corrosion susceptibility is greatly weakened in the as-extruded alloy,especially in the extrusion direction.The relatively uniform corrosion morphology of the as-extruded alloy is attributed to refined Mg_(2)Sn particles,uniform distribution of Mg_(2)Sn particles and favorable crystal orientation.Meanwhile,the cytotoxicity tests confirm that the Mg–5Sn–3In alloy exhibits cytotoxicity of Grade 0−1 for NIH3T3 cells,suggesting an acceptable cytotoxicity of this alloy in the vitro assay.展开更多
基金National Natural Science Foundation of China(Nos.52301041,52022017,52065009,52371005)Special Fund for Special Posts of Guizhou University,China(No.[2023]26)+1 种基金Science and Technology Planning Project of Guizhou Province,China(No.ZK2021269)Fundamental Research Funds for the Central Universities,China(No.DUT23YG104)。
文摘Microstructural characterization,mass loss tests,hydrogen evolution tests,electrochemical measurements,and corrosion morphology observations were conducted to investigate the effect of the secondary phases on the corrosion behavior of the as-cast Mg−7Sn−1Zn−1Y(TZW711)alloy after solution treatment(T4)and aging treatment(T6).The results show that the T4-TZW711 alloy possesses the highest corrosion resistance in the early corrosion stage.This is because the dissolution of Mg2Sn reduces the cathodic current density and increases the charge transfer resistance(Rct).When the corrosion time is prolonged,the undissolved and clustered MgSnY phase will peel off from the T4-TZW711 alloy surface,thereby increasing the corrosion rate of the alloy.After aging treatment,the undissolved MgSnY phase is dispersed,which results in a lower localized corrosion sensitivity of T6-TZW711 alloy than that of the T4-TZW711 alloy,suggesting that the T6 treatment can enhance the corrosion resistance of Mg−7Sn−1Zn−1Y alloys.
基金financially supported by the National Natural Science Foundation of China(Grant No.52201312).
文摘As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.This work establishes a dynamic behavior model of steel catenary risers(SCRs)with varying curvatures subjected to internal flow and external currents and considers the effects of pipe-soil interactions on the curvature profile.The governing equation is solved via the generalized integral transform technique(GITT),which yields a semi-analytical solution of a high-order nonlinear partial differential equation.Parametric studies are then performed to analyze the effects of varying curvature on the vibration frequency and amplitude of SCRs.The vibration frequency and amplitude increase with the touchdown angle and hang-off angle,although the effect of the hang-off angle is negligible.Additionally,as the curvature increases along the centerline axis,the position of the maximum amplitude of the SCR moves upward.
基金Project supported by the National Natural Science Foundation of China (52171030)the Key Basic Research Project of the Basic Strengthen Program (2021-JCJQ-ZD-043-00)the National Key Research and Development Program of China (2018YFA0702903)。
文摘Al-Cu-Mn alloys are widely used to produce automobile components like cylinder heads and engine blocks because of their capability to retain excellent thermal and mechanical characteristics at high temperatures.However,the Al-Cu-Mn-based alloys demonstrate restricted fluidity,leading to casting defects such as shrinkage and incomplete filling.This research investigated the microstructure and fluidity of Al-4.7Cu-1.0Mn-0.5Mg(wt%)alloy with minor cerium(Ce)addition.The as-cast alloys predominantly compriseα-Al matrix,accompanied by the presence of Al_(2)Cu,Al_(6)Mn,and Al_(8)Cu_(4)Ce phases.The influence of adding Ce on the fluidity of the Al-4.7Cu-1.0Mn-0.5Mg alloy was investigated using a trispiral fluidity test mold in this research.The findings suggest that the addition of Ce within the range of 0.1 wt%to 0.5 wt%in the Al-4.7Cu-1.0Mn-0.5Mg alloy results in an enhancement in fluidity.Specifically,the alloy containing 0.4 wt%Ce exhibits a significant increase in fluidity distance,from 349.7 to 485.7 mm.This improvement can be attributed to the reduction in viscosity,the refinement of secondary dendrite arm spacing,and the modification of secondary phase particles.However,a higher concentration of Ce leads to a decrease in fluidity length,potentially due to the formation of Al_(8)Cu_(4)Ce.
基金supported by the Natural Science Foundation of Liaoning Province(2023-MSBA-020)the Fundamental Research Funds for Central Universities(DUT24MS020)Science and Technology Innovation Fund of Dalian(2022JJ13SN073).
文摘Ferroptosis is a novel form of cell death driven by oxidative damage,and is implicated in various pathological conditions,including neurodegenerative diseases,retinal damage,and ischemia-reperfusion injury of organs.Inhibiting ferroptosis has shown great promise as a therapeutic strategy for these diseases,underscoring the urgent need to develop effective ferroptosis inhibitors.Although Ferrostatin-1(Fer-1)is a potent ferroptosis inhibitor,its susceptibility to oxidation and metabolic inactivation limits its clinical utility.In this study,the accumulation of peroxides and the resulting oxidative damage in the cellular microenvironment during ferroptosis were utilized to design Ferrostatin-1 prodrugs with reactive oxygen species-responsive features.This approach led to the development of a series of ferroptosis inhibitors that were capable of recognizing oxidative damage in diseased areas,allowing for targeted release and improved stability.The novel compounds demonstrated significant inhibitory effects and selectivity against RSL-3-induced ferroptosis in HK-2 cells,with compound a1 exhibiting an EC50 of 15.4�0.7μM,outperforming Fer-1.These compounds effectively identify the oxidative microenvironment associated with ferroptosis,enabling the targeted release of Fer-1,which prevents lipid peroxide accumulation and inhibits ferroptosis.This strategy holds promise for treating diseases related to ferroptosis,offering a targeted and intelligent therapeutic approach.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U1906233 and 52201312)Dalian High-Level Talent Innovation Program(Grant No.2021RD16)the Natural Science Foundation of Liaoning Province of China(Grant No.2023-BSBA-052).
文摘The carcass layer is the innermost structure of flexible marine risers and is responsible for resisting external pressure.It has an“S”section with a spiral interlocking feature.After the multi-pass roll forming of a flat steel strip,a carcass layer is formed by lock forming.During roll forming,the steel strip undergoes significant plastic deformation,and its local area accumulates residual stress owing to multiple loading and unloading cycles.These phenomena complicate the design and analysis of the carcass layer multi-pass roll forming(CLMRF)process and cause issues in the carcass layer during manufacturing,such as strip fracture and low forming quality.Thus,herein,CLMRF was investigated to clarify the stress distribution,and a parameter analysis was performed.First,the CLMRF process was designed on the basis of classical roll-forming design theory.Second,a finite element model was established,and CLMRF was simulated.Third,the distributions of the forming stress and residual stress of the strip during CLMRF were investigated.Finally,the influences of the strip thickness,roll gap,roll distance,and angular increment were investigated.The conclusions of this study can be used to provide technical guidance in the manufacturing of flexible risers.
基金support of the Natural Science Foundation of China(Nos.U23A20611 and 52071050)the Innovation and Entrepreneurship of High-level Talents Project of Dalian(No.2020RD07)the Science and Technology Innovation Project of Ningbo(No.2024Z077).
文摘Phosphor bronze is a commonly used elastic copper alloy,widely applied in electronic connectors and terminals[1-4].With the rapid development of 5 G mobile communication technology and the new energy vehicle industry,the size requirements for connectors have been reduced,while the demand for strength has gradually increased[5].This requires the alloy to possess higher strength and better deformability.
基金supported by the Fundamental Research Funds for the Central Universities(Nos.DUT23YG137 and DUT22LAB601)Liaoning Binhai Laboratory(No.LBLB-202303)+1 种基金Liaoning Province Science and Technology Joint Fund(Nos.2023JH2/101800039 and 2023JH2/101800037)National Natural Science Foundation of China(Nos.21925802,22090011,and 21878039)。
文摘Mitochondria are crucial organelles responsible for maintaining cell growth,and their homeostasis is closely linked to p H regulation.Physiologically,mitochondria exhibit a weakly alkaline state(pH~8.0).However,when subjected to stress stimuli that cause damage,cells initiate the process of mitophagy,resulting in mitochondrial acidification.Therefore,monitoring changes in mitochondrial p H to comprehend the physiological processes associated with mitophagy is essential.In this study,we developed an asymmetric pentamethine cyanine dye Cy5.5-H-Cy N as a probe for continuous monitoring of mitophagy in living cells.By incorporating an azaindole structure into the dye molecule,a ratiometric fluorescence response was achieved that is specifically responsive to p H variations while preserving its ability to target mitochondria and emit near-infrared fluorescence.Through various methods inducing mitophagy,Cy5.5-H-Cy N was employed to determine mitochondrial p H quantitatively,demonstrating its suitability as an ideal probe for continuous monitoring of mitophagy in living cells.
基金the National Key Research and Development Program of China(No.2018YFE0306103)the National Natural Science Foundation of China(No.52071050)+1 种基金the Science and Technology Innovation Project of Ningbo,China(No.2021Z032)the Program of China Scholarships Council(No.202106060148).
文摘The Cu/1010 steel bimetal laminated composites(BLCs)were rolled to different thicknesses to investigate the effect of rolling direction and reduction on the microstructure evolution and mechanical properties.The difference of mechanical properties between the Cu and 1010 steel causes different thickness reductions,percentage spread,and cladding ratios.The formation of strong texture induces larger strength of the rolled samples,and as the volume fraction of 1010 steel is larger in Route-A,its strength is consistently greater than that in Route-B.The obstruction of interface to crystal and dislocation slip results in the formation of interface distortion,inducing dislocation density gradient when the rolling reduction is low in Route-A.The slip planes of the Cu and 1010 steel are more prone to suffer the normal strain,while the shear strain of other crystal planes is obviously larger than the normal strain under rolling load near the interface.
基金the support of the National Key Research and Development Program of China(No.2018YFE0306103)the National Natural Science Foundation of China(No.52071050)the Science and Technology Innovation Project of Ningbo,China(No.2021Z032).
文摘To optimize the comprehensive properties of Ni−Si precipitation strengthened phosphor bronze,the impact of the Ni/Si mass ratio and heat treatment process on a Cu−8Sn−0.1P−1Ni−xSi alloy was explored.High resolution field emission scanning electron microscopy and transmission electron microscopy were used for microstructural characterization.The results indicate that the properties are influenced by the Ni/Si mass ratio,attributed to the formation of various second phases.Simultaneously,by influencing the diffusion rate,the microstructures and properties are influenced by the solid solution treatment.The strength is enhanced by precipitated nanoscale particles during the aging process by influencing the motion of dislocations.Ultimately,excellent comprehensive properties,including ultimate tensile strength,yield strength,and elongation of 866 MPa,772 MPa,and 8.7%,respectively,are obtained in the Cu−8Sn−0.1P−1Ni−0.227Si alloy.
基金supported by the National Natural Science Foundation of China[51974058,52371005,52022017,51927801]the Fundamental Research Funds for the Central Universities(DUT23YG104).
文摘In this work,the microstructure evolution and mechanical behavior of extruded SiC/ZA63 Mg matrix composites are investigated via combined experimental study and three-dimensionalfinite element modelling(3D FEM)based on the actual 3D microstructure achieved by synchrotron tomography.The results show that the average grain size of composite increases from 0.57μm of 8μm-SiC/ZA63 to 8.73μm of 50μm-SiC/ZA63.The type of texture transforms from the typicalfiber texture in 8μm-SiC/ZA63 to intense basal texture in 50μm-SiC/ZA63 composite and the intensity of texture increases sharply with increase of SiC particle size.The dynamic recrystallization(DRX)mechanism is also changed with increasing SiC particle size.Experimental and simulation results verify that the strength and elongation both decrease with increase of SiC particle size.The 8μm-SiC/ZA63 composite possesses the optimal mechanical property with yield strength(YS)of 383 MPa,ultimate tensile strength(UTS)of 424 MPa and elongation of 6.3%.The outstanding mechanical property is attributed to the ultrafine grain size,high-density precipitates and dislocation,good loading transfer effect and the interface bonding between SiC and matrix,as well as the weakened basal texture.The simulation results reveal that the micro-cracks tend to initiate at the interface between SiC and matrix,and then propagate along the interface between particle and Mg matrix or at the high strain and stress regions,and further connect with other micro-cracks.The main fracture mechanism in 8μm-SiC/ZA63 composite is ductile damage of matrix and interfacial debonding.With the increase of particle size,interface strength and particle strength decrease,and interface debonding and particle rupture become the main fracture mechanism in the 30μm-and 50μm-SiC/ZA63 composites.
基金supported by the Fundamental Research Funds for the Central Universities(No.DUT24YG142).
文摘This study constructed an in vitro blood-brain barrier(BBB)transwell model to investigate the regulatory effects and mechanisms of the photothermal effects of gold nanorods(AuNRs)excited by the second near-infrared region(NIR-II)on BBB permeability.The experimental results showed that the photothermal effects of NIR-II t AuNRs significantly decreased trans-epithelial electrical resistance(TEER)and increased the permeability of fluorescein isothiocyanate(FITC)-dextran,indicating that it can effectively open the BBB.This effect was reversible,and the TEER and FITC permeability returned to baseline levels within 24 h after treatment.Mechanistic studies revealed that BBB opening did not rely on apoptosis,cytoskeletal disruption,mitochondrial dysfunction,or inflammation.The opening of the BBB was closely associated with a temporary decrease in the expression and conformational change of the tight junction protein occludin due to the photothermal effect.Molecular simulations and docking analysis revealed that the heat shock protein HSP70 could bind to the conformationally altered occludin,supporting the regulatory role of photothermal effects on tight junction proteins.In summary,NIR-II t AuNRs achieved safe and reversible opening of the BBB by regulating the conformation and expression of tight junction proteins,providing a deeper insight for further research on BBB and the treatment of neurological diseases.
基金financially supported by the National Natural Science Foundation of China(Nos.52271025,51927801,and U22A20174)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZC20240173)+1 种基金the Science and Technology Planning Project of Liaoning Province(2023JH2/101700295)the Innovation Foundation of Science and the Technology of Dalian(No.2023JJ12GX021).
文摘Different from full-Heusler compounds,four vacancies in the face-centered cubic crystal structure provide extra sites for enhancing the thermoelectric properties of half-Heusler compounds(HHs).Herein,excess Ag is introduced to the Ni-site vacancies of ZrNiSn to optimize thermoelectric properties.The ZrNiAg_(x)Sn(x=0,0.01,0.02,and 0.03)samples were synthesized by levitation melting and spark plasma sintering.Remarkably,the introduction of excess Ag significantly improves the Seebeck coefficient of ZrNiAg_(0.01)Sn,and a peak power factor of~4.52 mW/(m K^(2))is achieved in ZrNiAg_(0.01)Sn at 923 K,which is enhanced by 22.8%than that of pristine ZrNiSn.As a result,the figure of merit zT of pristine ZrNiSn is enhanced from~0.60 to~0.72 of ZrNiAg_(0.01)Sn at 923 K.Additionally,grain refinement effectively increases the Vickers hardness of ZrNiAg_(0.01)Sn,which is enhanced by 32.8%than that of pristine ZrNiSn.These results demonstrate a viable doping strategy for designing ZrNiSn-based HHs with excellent thermoelectric and mechanical properties.
基金supported by the National Natural Science Foundation of China(No.52301041)the Guizhou Provincial Basic Research Program(No.QianKeHeJiChu-ZK[2024]YiBan036)+1 种基金the Special Fund for Special Posts of Guizhou University(No.[2023]26)the Fundamental Research Funds for the Central Universities.E.G.thanks support from Xiaomi Foundation.
文摘This study develops novel Mg-Sn-In-Ga alloys as potential implant materials for orthopedic applications.The corrosion behavior of the Mg-Sn-In-Ga alloys was studied through mass loss measurements,hydrogen evolution measurements,electrochemical analysis,and corrosion morphology observations.The results show that the corrosion rate of the Mg-1Sn-1In-1Ga alloy was only 0.10±0.003 mm/y after immersion in Hank’s solution for 15 days.This outstanding corrosion resistance was associated with the protective efect of the corrosion products.The increase in the Sn and Ga element content led to the precipitation of a large amount of Mg_(2)Sn and Mg_(5)Ga_(2),which had a dominant efect on the corrosion rate in the Mg-5Sn-1In-2Ga alloy.These precipitates increased the current density and detached from the alloy surface during the corrosion process.This can lead to a weakened protective efect of the corrosion layer,and thus generate localized corrosion and an increase in the corrosion rate.The strength of the Mg-5Sn-1In-2Ga alloy was enhanced due to fne-grain strengthening and precipitation strengthening.The ultimate tensile strength and yield strength of the Mg-5Sn-1In-2Ga alloy were~309 MPa and~253 MPa,respectively.
基金supported by the National Natural Science Foundation of China Excellent Young Scientist Fund(22422801)the National Natural Science Foundation of China General Project(22278053)+1 种基金the National Natural Science Foundation of China General Project(22078041)Dalian High-level Talents Innovation Support Program(2023RQ059).
文摘G protein coupled receptor kinase 2 (GRK2) is a kinase that regulates cardiac signaling activity. Inhibiting GRK2 is a promising mechanism for the treatment of heart failure (HF). Further development and optimization of inhibitors targeting GRK2 are highly meaningful. Therefore, in order to design GRK2 inhibitors with better performance, the most active molecule was selected as a reference compound from a data set containing 4-pyridylhydrazone derivatives and triazole derivatives, and its scaffold was extracted as the initial scaffold. Then, a powerful optimization-based framework for de novo drug design, guided by binding affinity, was used to generate a virtual molecular library targeting GRK2. The binding affinity of each virtual compound in this dataset was predicted by our developed deep learning model, and the designed potential compound with high binding affinity was selected for molecular docking and molecular dynamics simulation. It was found that the designed potential molecule binds to the ATP site of GRK2, which consists of key amino acids including Arg199, Gly200, Phe202, Val205, Lys220, Met274 and Asp335. The scaffold of the molecule is stabilized mainly by H-bonding and hydrophobic contacts. Concurrently, the reference compound in the dataset was also simulated by docking. It was found that this molecule also binds to the ATP site of GRK2. In addition, its scaffold is stabilized mainly by H-bonding and π-cation stacking interactions with Lys220, as well as hydrophobic contacts. The above results show that the designed potential molecule has similar binding modes to the reference compound, supporting the effectiveness of our framework for activity-focused molecular design. Finally, we summarized the interaction characteristics of general GRK2 inhibitors and gained insight into their molecule-target binding mechanisms, thereby facilitating the expansion of lead to hit compound.
基金supported by the National Key Research and Development Program of China(No.2022YFB3400142)the National Natural Science Foundation of China(Nos.52174356,51971051 and U22A20174)+2 种基金the Science and Technology Plan Project of Liaoning Province(Nos.2022010005-JH6/1001 and 2022JH2/1013)the Major Science and Technology Projects of Longmen Laboratory(No.231100220400)the Fundamental Research Funds for the Central Universities.
文摘The development of a new generation of high-performance Al alloys,achieved through Sc/Zr-modified Al-Mg-based alloys,is attracting growing attention.However,the significant cost associated with Sc presents a barrier to further advancement.In this study,the inclusion of trace heterogeneous TiB_(2)particles is employed to regulate the microstructural evolution process,thereby achieving high-performance aluminum alloys with optimal strength-ductility characteristics with minimal Sc addition.The ultimate tensile strength of Al-Mg-Sc-Zr-TiB_(2)alloy reached 442.4 MPa,with a elongation of 16.6%.The combined impact of TiB_(2)particles and Al_(3)(Sc,Zr)precipitates on the microstructure evolution of the Al-Mg alloy during hot deformation was investigated.It was observed that spherical Al_(3)(Sc,Zr)precipitates with sizes ranging from 5 to 10 nm dispersed in the matrix,during the hot deformation process,functioned as Zener pinning sites for dislocations,thus increasing the proportion of low-angle grain boundaries(LAGBs)and suppressing the dynamic recrystallization(DRX)process.The incorporation of trace TiB_(2)particles induced the particle-stimulated nucleation effect,accelerating DRX and refining the microstructure.The density of LAGBs further increased,and the proportion of continuous dynamic recrystallization also rose.Furthermore,the TiB_(2)particles mitigated the anisotropy of material and inhibited DRX grain growth,thereby expanding the subsequent processing window and offering more potential applications for the materials.This study provides new insights into the production of high-performance Al alloy products.
基金supported by the National Natural Science Foundation of China[52171030]the National Key Research and Development Program of China[2018YFA0702903]。
文摘In this study,a NbB_(2)/AZ91 composite exhibiting desirable mechanical properties was fabricated using a sample casting technique,followed by hard-plate rolling and short-term annealing.The effect of NbB_(2)particles on the microstructural evolution of the AZ91 alloy was investigated.The presence of NbB_(2)was shown to have a grain-refining effect on the AZ91 alloy and promoted dynamic recrystallization(DRX)and precipitation of fine Mg_(17)Al_(12)phases via particle-stimulated nucleation(PSN).Tensile testing revealed substantial enhancements in the ultimate tensile strength(UTS),yield strength(YS),and elongation(EL)of the as-rolled AZ91 alloy,with values of 379 MPa,292 MPa,and 14.7%,respectively,owing to the incorporation of NbB_(2)particles.Annealing led to further enhancements in EL with slight reductions in UTS and YS(360 MPa,252 MPa,and 16.8%,respectively).Owing to grain refinement and the PSN effect of the NbB_(2)particles,a significant number of geometrically necessary dislocations(GNDs)were induced in the matrix during the rolling process,which reduces the nucleation barrier and increases the number of nucleation sites for the recrystallized grains and Mg_(17)Al_(12)precipitates.Meanwhile,many residual dislocations and fine Mg_(17)Al_(12)precipitates in the as-rolled alloys were annihilated during annealing,resulting in slight grain growth and coarsening.The strengthening mechanism of the NbB_(2)/AZ91 composite are mainly associated with grain-refinement strengthening,particle-induced dislocation strengthening,strengthening resulting from mismatching coefficients of thermal expansion(CTE),and heterodeformation-induced(HDI)strengthening.Textural weakening,increased activation of non-basal slip systems,more-uniform strain patterns resulting from NbB_(2)particles,and precipitation are mainly responsible for enhancing ductility.
基金financially supported by the National Natural Science Foundation of China(Nos.51771041,51774065,51671044 and 51901116)the National Key Research and Development Program of China(No.2017YFA0403803)。
文摘To evaluate the potential of high entropy alloys for marine applications,a new high entropy alloy coating of AlCrFeNiW_(0.2)Ti_(0.5)was designed and produced on Q235 steel via laser cladding.The microstructure,microhardness and tribological performances sliding against YG6 cemented carbide,GCr15 steel and Si_(3)N_(4)ceramic in seawater were studied in detail.The AlCrFeNiW_(0.2)Ti_(0.5)coating showed an anomalous’sunflower-like’morphology and consisted of BCC and ordered B2 phases.The microhardness was approximately 692.5 HV,which was 5 times higher than substrate.The coating showed more excellent tribological performances than Q235 steel and SUS304,a typical material used in seawater environment,sliding against all three coupled balls in seawater.Besides,the wear and friction of AlCrFeNiW_(0.2)Ti_(0.5)coating sliding against YG6 in seawater were most mild.The main reason was the generation of Mg(OH)_(2),CaCO_(3),metal oxides and hydroxides and the formation of protective tribo-film on the worn surface of AlCrFeNiW_(0.2)Ti_(0.5)coating in the process of reciprocated sliding.This would effectively hinder the direct contact between the worn surfaces of AlCrFeNiW_(0.2)Ti_(0.5)coating and YG6 ball,resulting in a decrease of friction coefficient and wear rate.Thus the YG6 was an ideal coupled material for AlCrFeNiW_(0.2)Ti_(0.5)coating in seawater,and the coating would become a promising wear-resisting material in ocean environment.
基金financially supported by the National Key Research and Development Program of China(Nos.2018YFA0702903,2016YFB0701204)the Fundamental Research Funds for the Central Universities,China(No.DUT20GF102)。
文摘In order to broaden the application of wrought Mg alloy sheets in the automotive industry,the influence of Ca and Sm alloying on the texture evolution,mechanical properties,and formability of a hot-rolled Mg-2Zn-0.2Mn alloy was investigated by OM,XRD,SEM,EBSD,tensile tests,and Erichsen test.The results showed that the average grain size and basal texture intensity of Mg-2Zn-0.2Mn alloys were remarkably decreased after Ca and Sm additions.0.64 wt.%Ca or 0.48 wt.%Sm addition significantly increased the tensile strength,ductility and formability.Moreover,the synergetic addition of Sm and Ca improved the ductility and formability of Mg-2Zn-0.2Mn alloy,which was due to the change of Ca distribution and further reduction of the size of Ca-containing particles by Sm addition.The results provided a possibility of replacing RE elements with Ca and Sm in Mg alloys which bring about outstanding mechanical properties and formability.
基金provided by National Key R&D Program of China(2018YFB1106400)National Natural Science Foundation of China(11672057,11702052,U1906233)+1 种基金Aeronautical Science Foundation of China(2018ZB63002)China Postdoctoral Science Foundation(2018M640251,2019T120201)。
文摘The anti-bird-strike performance of a lattice-material-infilled curved plate is investigated herein.Since automatically filling the curved structure by classical lattice material filling methods will cause a large number of manufacturing defects,a space-dependent lattice material filling method for the curved plate is firstly proposed in this paper Next,using a face-centered cubic lattice,a lattice-material-infilled test piece with a hollow ratio of 40.8%is built.The test pieces are manufactured via additive manufacturing using titanium alloy.In bird-strike experimental tests,the test pieces are crashed against gelatin birds at an impact velocity of 200 m/s.Dynamic strain gauges are used to record the crash history and the results are discussed.Furthermore,a numerical analysis to simulate the bird-strike experiment is performed.The results from the experimental tests and numerical simulation agree well.This work shows that the lattice-material-infilled curved plate yields promising bird-strike resistance.Therefore,lattice-infilled materials are feasible for protecting aerospace components against bird-strike as well as for reducing the component weight.
基金the National Key Research and Development Program of China(No.2017YFA0403803)the National Natural Science Foundation of China(Nos.52022017,51974058,51525401,51927801,81974325)+1 种基金the Science and Technology Commission of Shanghai Municipality,China(No.18ZR1428700)the Liaoning Revitalization Talents Program,China(No.XLYC1808005).
文摘The microstructural observation,the mass loss test,potentiodynamic polarization measurements and corrosion morphology examinations were conducted to study the influence of microstructural characteristics on corrosion behavior of Mg–5Sn–3In alloys in Hank’s solution after extrusion.The results show that the corrosion rate of the as-cast alloy is similar to that of as-extruded alloy;however,the local corrosion susceptibility is greatly weakened in the as-extruded alloy,especially in the extrusion direction.The relatively uniform corrosion morphology of the as-extruded alloy is attributed to refined Mg_(2)Sn particles,uniform distribution of Mg_(2)Sn particles and favorable crystal orientation.Meanwhile,the cytotoxicity tests confirm that the Mg–5Sn–3In alloy exhibits cytotoxicity of Grade 0−1 for NIH3T3 cells,suggesting an acceptable cytotoxicity of this alloy in the vitro assay.
