Improving and optimizing the target properties of ceramics via the high entropy strategy has attracted significant attention.Rare earth niobate is a potential thermal barrier coating(TBCs)material,but its poor high-te...Improving and optimizing the target properties of ceramics via the high entropy strategy has attracted significant attention.Rare earth niobate is a potential thermal barrier coating(TBCs)material,but its poor high-temperature phase stability limits its further application.In this work,four sets of TBCs high-entropy ceramics,(Sm_(1/5)Dy_(1/5)Ho_(1/5)Er_(1/5)Yb_(1/5))(Nb_(1/2)Ta_(1/2))O_(4)(5NbTa),(Sm_(1/6)Dy_(1/6)Ho_(1/6)Er_(1/6)Yb_(1/6)Lu_(1/6))(Nb_(1/2)Ta_(1/2))O_(4)(6NbTa),(Sm_(1/7)Gd_(1/7)Dy_(1/7)Ho_(1/7)Er_(1/7)Yb_(1/7)Lu_(1/7))(Nb_(1/2)Ta_(1/2))O_(4)(7NbTa),(Sm_(1/8)Gd_(1/8)Dy_(1/8)Ho_(1/8)Er_(1/8)Tm_(1/8)Yb_(1/8)Lu_(1/8))(Nb_(1/2)Ta_(1/2))O_(4)(8NbTa)are synthesized using a solid-state reaction method at 1650℃for 6 h.Firstly,the X-ray diffractometer(XRD)patterns display that the samples are all single-phase solid solution structures(space group C 2/c).Differential scanning calorimetry(DSC)and the high-temperature XRD of 8NbTa cross-check that the addition of Ta element in 8HERN increases the phase transition temperature above 1400℃,which can be attributed to that the Ta/Nb co-doping at B site introduces the fluctuation of the bond strength of Ta-O and Nb-O.Secondly,compared to high-entropy rare-earth niobates,the introduction of Ta atoms at B site substantially reduce thermal conductivity(re-duced by 44%,800℃)with the seven components high entropy ceramic as an example.The low thermal conductivity means strong phonon scattering,which may originate from the softening acoustic mode and flattened phonon dispersion in 5–8 principal element high entropy rare earth niobium tantalates(5–8NbTa)revealed by the first-principles calculations.Thirdly,the Ta/Nb co-doping in 5–8NbTa systems can further optimize the insulation performance of oxygen ions.The oxygen-ion conductivity of 8NbTa(3.31×10^(−6)S cm^(−1),900℃)is about 5 times lower than that of 8HERN(15.8×10^(−6)S cm^(−1),900℃)because of the sluggish diffusion effect,providing better oxygen barrier capacity in 5–8NbTa systems to inhibit the overgrowth of the thermal growth oxide(TGO)of TBCs.In addition,influenced by lattice dis-tortion and solid solution strengthening,the samples possess higher hardness(7.51–8.15 GPa)and TECs(9.78×10^(−6)K−1^(-1)0.78×10^(−6)K^(−1),1500℃)than the single rare-earth niobates and tantalates.Based on their excellent overall properties,it is considered that 5–8NbTa can be used as auspicious TBCs.展开更多
The microstructural evolution,phase stability,and mechanical properties of Al-Li-Mg-Ti-M(M=Zn,Zr,V)lightweight high-entropy alloys(LW-HEAs)were investigated.The LW-HEAs with three components,Al_(20)Li_(20)Mg_(10)-Ti_(...The microstructural evolution,phase stability,and mechanical properties of Al-Li-Mg-Ti-M(M=Zn,Zr,V)lightweight high-entropy alloys(LW-HEAs)were investigated.The LW-HEAs with three components,Al_(20)Li_(20)Mg_(10)-Ti_(40)Zn_(10)(#Zn),Al_(20)Li_(20)Mg_(10)Ti_(30)Zr_(20)(#Zr),and Al_(20)Li_(20)Mg_(10)Ti_(30)V_(20)(#V),were designed according to the thermo-dynamic design criteria of HEA,and prepared via a combination process of mechanical alloying and cold-press sintering.The effects of alloy composition and sintering temperature on the microstructure and mechanical properties of the LW-HEAs were studied.The results show that the as-milled Al-Li-Mg-Ti-M(M=Zn,Zr,V)LW-HEAs form a simple structure with HCP-type solid solution as the primary phase,a dual-HCP type solid solution phase,and a BCC phase,respectively.After cold-press sintering,the#Zn and#V alloys undergo obvious phase transformation;while the#Zr alloy with dual-HCP phases exhibits the best phase stability during heat treatment.The#V-750°C alloy demonstrates the maximum hardness and specific strength of HV 595.2 and 625 MPa∙cm3/g,respectively,under the combined effect of solid solution strengthening of BCC phase and precipitation strengthening ofβ-AlTi_(3).Moreover,the#Zr-650°C,#Zr-750°C,and#Zn-650°C alloys are expected to have excellent plasticity.展开更多
Ti-Hf-Zr-Nb-Ta refractory high-entropy alloys(RHEAs)exhibiting a dual-phase structure resulting from martensitic transformation offer significant ductility enhancement,but their design requires precise control of the ...Ti-Hf-Zr-Nb-Ta refractory high-entropy alloys(RHEAs)exhibiting a dual-phase structure resulting from martensitic transformation offer significant ductility enhancement,but their design requires precise control of the phase stability between body-centred cubic(BCC)and hexagonal close-packed(HCP)phases.This study establishes a comprehensive thermodynamic database for the Ti-Hf-Zr-Nb-Ta system using the 3rd-generation Calculation of Phase Diagrams(CALPHAD)model.The reliability of the database is validated by the strong agreement between the calculated thermodynamic properties and phase equilibria and the experimental data for pure element,as well as for binary and ternary systems.Utilizing this database,the phase stability of various RHEAs within this system was predicted,showing that all RHEAs exhibit a BCC single phase over a wide temperature range.The HCP phase is stable and coexists with BCC phase in both quaternary and quinary RHEAs at lower temepratures.Calculations of the Gibbs energy difference between the BCC and HCP phases(ΔG^(HCP−BCC))in TiHfZrTa_(x) and TiHfZrNb_(x) alloys reveal that both Nb and Ta stabilize the BCC phase,with Nb exerting a stronger influence.Significantly,a metastable BCC+HCP region in the TiHfZrTa_(x) and TiHfZrNb_(x) alloys with ΔG^(HCP−BCC) ranging from 1786 to 2230 J/mol.Utilizing this finding,the critical Nb composition range(0.0367–0.0712)to achieve the metastable BCC+HCP phase is precisely predicted in TiHfZrTa_(0.2)Nb_(x) alloys,enabling targeted design for martensitic transformation.The predictions show excellent agreement with existing experimental measurements.展开更多
First-principles calculations were carried out to investigate the structural stabilities and electronic properties of RhZr.The plane wave based pseudopotential method was used,in which both the local density approxima...First-principles calculations were carried out to investigate the structural stabilities and electronic properties of RhZr.The plane wave based pseudopotential method was used,in which both the local density approximation（LDA） and the generalized gradient approximation（GGA） implanted in the CASTEP code were employed.The internal positions of atoms in the unit cell were optimized and the ground state properties such as lattice parameter,density of state,cohesive energies and enthalpies of formation of ortho-RhZr and cubic-RhZr were calculated.The calculation results indicate that ortho-RhZr can form more easily than cubic-RhZr and the ortho-RhZr is more stable than cubic-RhZr.The density of states（DOS） reveals that the strong bonding in the Rh-Zr and Rh-Rh or Zr-Zr interaction chains accounts for the structural stability of ortho-RhZr and the hybridization between Rh-4d states and Zr-4d states is strong.展开更多
An investigation of electronic property and high pressure phase stability of SmN has been conducted using first principles calculations based on density functional theory. The elec- tronic properties of Stun show a st...An investigation of electronic property and high pressure phase stability of SmN has been conducted using first principles calculations based on density functional theory. The elec- tronic properties of Stun show a striking feature of a half metal, the majority-spin electrons are metallic and the minority-spin electrons are semiconducting. It was found that Stun undergoes a pressure-induced phase transition from NaCl-type （B1） to CsCl-type structure （B2） at 117 GPa. The elastic constants of Stun satisfy Born conditions at ambient pressure, indicating that B1 phase of SmN is mechanically stable at 0 GPa. The result of phonon spectra shows that B1 structure is dynamically stable at ambient pressure, which agrees with the conclusion derived from the elastic constants.展开更多
The microstructure evolution and phase composition of an α+β titanium alloy, Ti-3Al-5Mo-4.5V(wt.%),have been investigated. Electron probe micro analysis(EPMA) quantitative results manifest that the stability of β p...The microstructure evolution and phase composition of an α+β titanium alloy, Ti-3Al-5Mo-4.5V(wt.%),have been investigated. Electron probe micro analysis(EPMA) quantitative results manifest that the stability of β phase decreases with increasing quenching temperature, which is influenced by the significant variation of β-stabilizing elements concentration. Detailed microstructure analysis shows that the β→ωphase transformation does occur when quenching at 750℃ and 800 ℃. The ω-reflections change from incommensurate ω-spots(750 ℃) to ideal ω-spots(800 ℃) as the β stability of the alloy decreases. Further the decrease of β phase stability encourages the formation of athermal α " martensite, which has the following orientation relationships: [111]β//[110]α",[100]p//[100]α " and [-110]p//[00-1]α" with respect to the β matrix.展开更多
The phase stability,elastic properties and electronic structures of three typical Mg-Y intermetallics including Mg_(24)Y_(5),Mg_(2)Y and MgY are systematically investigated using first-principles calculations based on...The phase stability,elastic properties and electronic structures of three typical Mg-Y intermetallics including Mg_(24)Y_(5),Mg_(2)Y and MgY are systematically investigated using first-principles calculations based on density functional theory.The optimized structural parameters including lattice constants and atomic coordinates are in good agreement with experimental values.The calculated cohesive energies and formation enthalpies show that either phase stability or alloying ability of the three intermetallics is gradually enhanced with increasing Y content.The single-crystal elastic constants C_(ij) of Mg-Y intermetallics are also calculated,and the bulk modulus B,shear modulus G,Young's modulus E,Poisson ratio v and anisotropy factor A of polycrystalline materials are derived.It is suggested that the resistances to volume and shear deformation as well as the stiffness of the three intermetallics are raised with increasing Y content.Besides,these intermetallics all exhibit ductile characteristics,and they are isotropic in compression but anisotropic to a certain degree in shear and stiffness.Comparatively,Mg_(24)Y_(5) presents a relatively higher ductility,while MgY has a relatively stronger anisotropy in shear and stiffness.Further analysis of electronic structures indicates that the phase stability of Mg-Y intermetallics is closely related with their bonding electrons numbers below Fermi level.Namely,the more bonding electrons number below Fermi level corresponds to the higher structural stability of Mg-Y intermetallics.展开更多
Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenchi...Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenching temperature variation from dual α+β field(700℃) to single β field(880℃). Tensile tests at ambient temperature show that apparent yield strength of the alloy experiences an abrupt decrease followed by a significant increase from 700℃ to 880℃. Work hardening behavior is characterized by transition from the initial two-regime feature to the three-stage outlook. Concurrently, the maximum working hardening rate drops from 14000 MPa to 3000 MPa, which is concurrent with the shrinking volume fraction of primary a phase. Detailed discussion about the relationship between deformation mechanisms and β phase stability has been outlined.展开更多
Two experimental single crystal superalloys, the Ru-free alloy and the Ru-containing alloy with [001 ] orientation, were cast in a directionally solidified furnace, while other alloying element contents were kept unch...Two experimental single crystal superalloys, the Ru-free alloy and the Ru-containing alloy with [001 ] orientation, were cast in a directionally solidified furnace, while other alloying element contents were kept unchanged. The effects of Ru on the microstructure and phase stability of the single crystal superalloy were investigated, y＇ directional coarsening and rafting were observed in the Ru-free alloy and Ru-containing alloy after long-term aging at 1070~C for 800 h. Needle-shaped o topologically close packed （TCP） phases precipitated and grew along the fixed direction in both the alloys. The precipitating rate and volume fraction of TCP phases decreased significantly by adding Ru. The compositions ofy and y＇ phases measured using an energy-dispersive X-ray spectroscope （EDS） in transmission electron microscopy （TEM） analysis showed that the addition of Ru lessened the partition ratio of TCP forming elements, Re, W and Mo, and decreased the satu- ration degrees of these elements in y phase, which can enable the Ru-containing alloy to be more resistant to the formation of TCP phases. It is indicated that the addition of Ru to the Ni-based single crystal superalloy with high content of the refractory alloying element can enhance phase stability.展开更多
Formation, solution and phase change of hydration products in MgO-MgCl2-H2O system was studied with thermodynamics method, and resistance to water immersion and phase change of magnesium oxychloride cement with differ...Formation, solution and phase change of hydration products in MgO-MgCl2-H2O system was studied with thermodynamics method, and resistance to water immersion and phase change of magnesium oxychloride cement with different MgO/MgCl2 molar ratio was experimented. The results show that pH value of immersion solution of cement paste has a remarkable influence on phase stability of hydration products. A higher pH value leads to a lower solubility and a better phase stability of hydration products. When the solution pH value is higher than 10.37, the precipitation of much Mg（OH）2 crystal induces a worse phase stability of hydration products. With the increasing MgO/MgCl2 molar ratio （lower than 6）, the more amount of MgO in the hydration products enhances the alkalinity of solution and the phase stability is improved. However, when the MgO/MgCl2 molar ratio is higher than 6 and the excessive MgO exsits in the hydration products, the cement paste may be damaged by the excessive crystallization stress of a great deal of Mg（OH）2 formation.展开更多
In this study, high-entropy films with the compo- sition of NbTiA1SiNx were prepared by a reactive direct current （DC） magnetron sputtering technique, with different nitrogen flow rates （0, 4 and 8 ml.min^-1）. The...In this study, high-entropy films with the compo- sition of NbTiA1SiNx were prepared by a reactive direct current （DC） magnetron sputtering technique, with different nitrogen flow rates （0, 4 and 8 ml.min^-1）. The microstructures and properties were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high-resolution transmission electron microscopy （HRTEM）, nano-indenter and spectrophotometer. All of the as-deposited NbTiA1SiNx films are shown to have an amorphous structure, and the films exhibit high thermal stability up to 700℃. The maximum hardness and modulus values of the films reach 20.5 GPa （4 ml.min-1） and 206.8 GPa （0 ml.min^-l）, respectively. The films exhibit high absorption of the solar energy in the wavelength of 0.3-2.5 pm, which indicates that NbTiA1SiNx nitride film is a potential candidate solar selective absorbing coating for high-temperature photo-thermal conversion in the concentrated solar power project.展开更多
Electronic structure and elastic properties of Al_(2)Y,Al_(3)Y,Al_(2)Gd and Al_(3)Gd phases were investigated by means of first-principles calculations from CASTEP program based on density functional theory(DFT).The g...Electronic structure and elastic properties of Al_(2)Y,Al_(3)Y,Al_(2)Gd and Al_(3)Gd phases were investigated by means of first-principles calculations from CASTEP program based on density functional theory(DFT).The ground state energy and elastic constants of each phase were calculated,the formation enthalpy(ΔH),bulk modulus(B),shear modulus(G),Young's modulus(E),Poisson's ratio(ν)and anisotropic coefficient(A)were derived.The formation enthalpy shows that Al_(2)RE is more stable than Al_(3)RE,and Al-Y intermetallics have stronger phase stability than Al-Gd intermetallics.The calculated mechanical properties indicate that all these four intermetallics are strong and hard brittle phases,it may lead to the similar performance when deforming due to their similar elastic constants.The total and partial electron density of states(DOS),Mulliken population and metallicity were calculated to analyze the electron structure and bonding characteristics of the phases.Finally,phonon calculation was conducted,and the thermodynamic properties were obtained and further discussed.展开更多
High-temperature structural metals remain in high demand for aerospace aircraft,gas turbine engines,and nuclear power plants.Refractory high-entropy alloys(RHEAs)with superior mechanical properties at elevated tempera...High-temperature structural metals remain in high demand for aerospace aircraft,gas turbine engines,and nuclear power plants.Refractory high-entropy alloys(RHEAs)with superior mechanical properties at elevated temperatures are promising candidates for high-temperature structural materials.In this work,a WTaMoNbTi RHEA with adequate room temperature plasticity and considerable strength at 1600℃was fabricated by vacuum arc-melting.The room temperature fracture strain of the as-cast WTaMoNbTi RHEA was 7.8%,which was about 5.2 times that of the NbMoTaW alloy.The alloy exhibited a strong resistance to high-temperature softening,with a high yield strength of 173 MPa and compressive strength of 218 MPa at 1600℃.The WTaMoNbTi RHEA possessed excellent phase stability in the range of room temperature to 2000℃.The dendritic grains grew into equiaxed grains after compression test at 1600℃due to the dynamic recrystallization process at high temperature.This work presents a promising high-temperature structural material that can be applied at 1600℃.展开更多
Phase stability and its effect on tensile properties of MAR-M247 alloy have been investigated during thermal exposure at 800–900°C for up to 10,000 h.Detailed investigations reveal that the larger secondaryγ′p...Phase stability and its effect on tensile properties of MAR-M247 alloy have been investigated during thermal exposure at 800–900°C for up to 10,000 h.Detailed investigations reveal that the larger secondaryγ′phase has no obvious growth,but the smaller tertiaryγ′phase obviously coarsens and the coalescence occurs during thermal exposure at 850°C and below.γ′coarsening behavior is consistent with the description of Ostwald ripening theory beforeγ′coalescence.Hf-rich blocky MC carbide shows excellent thermal stability,but Ta-rich script-type MC carbide gradually degenerates via reaction,MC+γ→M_(23)C_(6)+γ′and finally formsγ film around MC and M_(23)C_(6) carbides.With increasing thermal exposure time,the tensile strength decreases.The ductility first increases and then decreases during exposure at 800°C,but it decreases continuously at 900°C.In addition,the ductility keeps almost constant when the exposure time is longer than 5000 h.展开更多
The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3...The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3 mol% Yb2O3 （GYb-YSZ） powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed.展开更多
The residual austenite and its stability in commercial 60Si2Mn steel treated by quenching and partitioning(Q-P)were investigated.The Q-P heat treatment was carried out using a system of ordinary electric furnace--oil ...The residual austenite and its stability in commercial 60Si2Mn steel treated by quenching and partitioning(Q-P)were investigated.The Q-P heat treatment was carried out using a system of ordinary electric furnace--oil bath box--electric furnace.Cryogenic treatments at different temperatures were performed to assess the thermal stability of residual austenite.The microstructure,particularly residual austenite,was analyzed using optical microscope and X-ray diffraction(XRD),and the microhardness and Rockwell hardness were measured.The residual austenite with the volume fraction as much as 13.7%and the HRC hardness level of 41 were achieved,and the residual austenite is relatively stable.展开更多
The characteristic crystal model is applied to the study of phase stability and thermodynamics in substitutional bcc-based Ta-W alloys.The basic principle and method of alloy thermodynamics which is described by the c...The characteristic crystal model is applied to the study of phase stability and thermodynamics in substitutional bcc-based Ta-W alloys.The basic principle and method of alloy thermodynamics which is described by the characteristic crystal model is introduced in detail.The Gibbs energy of various phases including both disordered and ordered phases of the Ta-W system are evaluated.The phase diagram of Ta-W alloys is assessed and predicted.The results are in good agreement with experiments and better than that of first principle.展开更多
The phase stability,magnetic properties,martensitic transformation,and electronic properties of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system with excess Mn have been systematically investigated by the first-principles calcul...The phase stability,magnetic properties,martensitic transformation,and electronic properties of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system with excess Mn have been systematically investigated by the first-principles calculations.Results indicate that the excess Mn atoms will directly occupy the sublattices of Ni(MnNi)or Sn(MnSn).The formation energy(Ef)of the austenite has a relationship with the Mn content:Ef=135.27(1+x+y)−293.01,that is,the phase stability of the austenite decreases gradually with the increase in Mn content.According to the results of the formation energy of austenite,there is an antiparallel arrangement of the magnetic moment between the excess and normal Mn atoms in the Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x=0 or y=0)system,while the magnetic moment direction of the normal Mn atoms arranges antiparallel to that of MnNi atoms and parallel to that of MnSn atoms in the Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x,y≠0)system.The martensitic transformation occurs in some Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x,y≠0)alloys with large magnetic moments of ferrimagnetic austenite.Besides,the valence electrons tend to distribute around the Ni or MnNi atoms and mainly bond with the normal Mn atoms.The results of this work can lay a theoretical foundation for further development of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system as the potential ferromagnetic shape memory alloys.展开更多
The effects of site occupation on the phase stability,martensitic transformation,and the magnetic and electronic properties of a full series of Ni-Mn-In alloys are theoretically studied by using the ab initio calculat...The effects of site occupation on the phase stability,martensitic transformation,and the magnetic and electronic properties of a full series of Ni-Mn-In alloys are theoretically studied by using the ab initio calculations.Results indicate that the excess atoms of the rich component directly take the sublattices of the deficient components of the Ni2Mn_(1+x)In_(1-x),Ni2-xMn_(1+x)In,and Ni_(2+x)Mn_(1-x)In alloys.Nevertheless,the mixed and indirect site occupations may coexist in the Ni_(2+x)Mn In_(1-x)system.The relevant magnetic configurations of the austenite for the four alloy systems have also been determined.The results show that,except for the austenite in the Ni2-xMn_(1+x)In alloys,which tend to be ferrimagnetic,the other alloys all present ferromagnetic austenite.Thus,the site occupation and associated magnetic states are the crucial influencing factors of the phase stability,martensitic transformation,and the total magnetic moment.The electronic structure of the austenite phase also shows that the covalent bonding plays an important role in the phase stability.The key finding of this work is both Ni2Mn_(1+x)In_(1-x)and Ni_(2+x)Mn In_(1-x)alloys serve as the potential shape memory alloys.展开更多
The all-d-metal Ni-Mn-Ti Heusler alloy has giant elastocaloric eff ect and excellent mechanical properties,which is diff erent from the conventional Ni-Mn-based Heusler alloys.In this work,the preferred site occupatio...The all-d-metal Ni-Mn-Ti Heusler alloy has giant elastocaloric eff ect and excellent mechanical properties,which is diff erent from the conventional Ni-Mn-based Heusler alloys.In this work,the preferred site occupation,phase stability,martensitic transformation,magnetic properties,and electronic structure of the B-doped Ni_(2)Mn_(1.5)Ti_(0.5)alloys are systematically investigated by the fi rst-principles calculations.The results show that B atoms preferentially occupy the octahedral interstitial.The doped B atoms tend to exist in the(Ni_(2)Mn_(1.5)Ti_(0.5))_(1-x)B_(x)(x=0.03,0.06,0.09)alloy in the form of aggregation distribution,and the martensitic transformation temperature decreases with the increase in the B content.For octahedral interstitial doping,the toughness and plasticity of the(Ni_(2)Mn_(1.5)Ti_(0.5))_(1-x)B_(x) alloys decrease,but the strength and rigidity are greatly enhanced.This is because a small part of the d-d hybridization in ternary Ni-Mn-Ti alloy is replaced by the p-d hybridization in Ni-Mn-Ti-B alloy.展开更多
基金support from Yunnan Major Scientific and Technological Projects(No.202302AG050010)Yunnan Fundamental Research Projects(Nos.202101AW070011 and202101BE070001–015)+1 种基金National Natural Science Foundation of China(No.52303295)Project Funds of“Xingdian Talent Support Program”.
文摘Improving and optimizing the target properties of ceramics via the high entropy strategy has attracted significant attention.Rare earth niobate is a potential thermal barrier coating(TBCs)material,but its poor high-temperature phase stability limits its further application.In this work,four sets of TBCs high-entropy ceramics,(Sm_(1/5)Dy_(1/5)Ho_(1/5)Er_(1/5)Yb_(1/5))(Nb_(1/2)Ta_(1/2))O_(4)(5NbTa),(Sm_(1/6)Dy_(1/6)Ho_(1/6)Er_(1/6)Yb_(1/6)Lu_(1/6))(Nb_(1/2)Ta_(1/2))O_(4)(6NbTa),(Sm_(1/7)Gd_(1/7)Dy_(1/7)Ho_(1/7)Er_(1/7)Yb_(1/7)Lu_(1/7))(Nb_(1/2)Ta_(1/2))O_(4)(7NbTa),(Sm_(1/8)Gd_(1/8)Dy_(1/8)Ho_(1/8)Er_(1/8)Tm_(1/8)Yb_(1/8)Lu_(1/8))(Nb_(1/2)Ta_(1/2))O_(4)(8NbTa)are synthesized using a solid-state reaction method at 1650℃for 6 h.Firstly,the X-ray diffractometer(XRD)patterns display that the samples are all single-phase solid solution structures(space group C 2/c).Differential scanning calorimetry(DSC)and the high-temperature XRD of 8NbTa cross-check that the addition of Ta element in 8HERN increases the phase transition temperature above 1400℃,which can be attributed to that the Ta/Nb co-doping at B site introduces the fluctuation of the bond strength of Ta-O and Nb-O.Secondly,compared to high-entropy rare-earth niobates,the introduction of Ta atoms at B site substantially reduce thermal conductivity(re-duced by 44%,800℃)with the seven components high entropy ceramic as an example.The low thermal conductivity means strong phonon scattering,which may originate from the softening acoustic mode and flattened phonon dispersion in 5–8 principal element high entropy rare earth niobium tantalates(5–8NbTa)revealed by the first-principles calculations.Thirdly,the Ta/Nb co-doping in 5–8NbTa systems can further optimize the insulation performance of oxygen ions.The oxygen-ion conductivity of 8NbTa(3.31×10^(−6)S cm^(−1),900℃)is about 5 times lower than that of 8HERN(15.8×10^(−6)S cm^(−1),900℃)because of the sluggish diffusion effect,providing better oxygen barrier capacity in 5–8NbTa systems to inhibit the overgrowth of the thermal growth oxide(TGO)of TBCs.In addition,influenced by lattice dis-tortion and solid solution strengthening,the samples possess higher hardness(7.51–8.15 GPa)and TECs(9.78×10^(−6)K−1^(-1)0.78×10^(−6)K^(−1),1500℃)than the single rare-earth niobates and tantalates.Based on their excellent overall properties,it is considered that 5–8NbTa can be used as auspicious TBCs.
基金financially supported by China Aeronautical Science Foundation (No.2023Z0530Q9002)the Program for Chongqing Talents,China (No.cstc2024ycjh-bgzxm0066)。
文摘The microstructural evolution,phase stability,and mechanical properties of Al-Li-Mg-Ti-M(M=Zn,Zr,V)lightweight high-entropy alloys(LW-HEAs)were investigated.The LW-HEAs with three components,Al_(20)Li_(20)Mg_(10)-Ti_(40)Zn_(10)(#Zn),Al_(20)Li_(20)Mg_(10)Ti_(30)Zr_(20)(#Zr),and Al_(20)Li_(20)Mg_(10)Ti_(30)V_(20)(#V),were designed according to the thermo-dynamic design criteria of HEA,and prepared via a combination process of mechanical alloying and cold-press sintering.The effects of alloy composition and sintering temperature on the microstructure and mechanical properties of the LW-HEAs were studied.The results show that the as-milled Al-Li-Mg-Ti-M(M=Zn,Zr,V)LW-HEAs form a simple structure with HCP-type solid solution as the primary phase,a dual-HCP type solid solution phase,and a BCC phase,respectively.After cold-press sintering,the#Zn and#V alloys undergo obvious phase transformation;while the#Zr alloy with dual-HCP phases exhibits the best phase stability during heat treatment.The#V-750°C alloy demonstrates the maximum hardness and specific strength of HV 595.2 and 625 MPa∙cm3/g,respectively,under the combined effect of solid solution strengthening of BCC phase and precipitation strengthening ofβ-AlTi_(3).Moreover,the#Zr-650°C,#Zr-750°C,and#Zn-650°C alloys are expected to have excellent plasticity.
基金financially supported by the Natural Science Foundation of Hebei Province,China(No.E202302154).
文摘Ti-Hf-Zr-Nb-Ta refractory high-entropy alloys(RHEAs)exhibiting a dual-phase structure resulting from martensitic transformation offer significant ductility enhancement,but their design requires precise control of the phase stability between body-centred cubic(BCC)and hexagonal close-packed(HCP)phases.This study establishes a comprehensive thermodynamic database for the Ti-Hf-Zr-Nb-Ta system using the 3rd-generation Calculation of Phase Diagrams(CALPHAD)model.The reliability of the database is validated by the strong agreement between the calculated thermodynamic properties and phase equilibria and the experimental data for pure element,as well as for binary and ternary systems.Utilizing this database,the phase stability of various RHEAs within this system was predicted,showing that all RHEAs exhibit a BCC single phase over a wide temperature range.The HCP phase is stable and coexists with BCC phase in both quaternary and quinary RHEAs at lower temepratures.Calculations of the Gibbs energy difference between the BCC and HCP phases(ΔG^(HCP−BCC))in TiHfZrTa_(x) and TiHfZrNb_(x) alloys reveal that both Nb and Ta stabilize the BCC phase,with Nb exerting a stronger influence.Significantly,a metastable BCC+HCP region in the TiHfZrTa_(x) and TiHfZrNb_(x) alloys with ΔG^(HCP−BCC) ranging from 1786 to 2230 J/mol.Utilizing this finding,the critical Nb composition range(0.0367–0.0712)to achieve the metastable BCC+HCP phase is precisely predicted in TiHfZrTa_(0.2)Nb_(x) alloys,enabling targeted design for martensitic transformation.The predictions show excellent agreement with existing experimental measurements.
基金Project(u0837601)supported by the National Natural Science Foundation of China
文摘First-principles calculations were carried out to investigate the structural stabilities and electronic properties of RhZr.The plane wave based pseudopotential method was used,in which both the local density approximation（LDA） and the generalized gradient approximation（GGA） implanted in the CASTEP code were employed.The internal positions of atoms in the unit cell were optimized and the ground state properties such as lattice parameter,density of state,cohesive energies and enthalpies of formation of ortho-RhZr and cubic-RhZr were calculated.The calculation results indicate that ortho-RhZr can form more easily than cubic-RhZr and the ortho-RhZr is more stable than cubic-RhZr.The density of states（DOS） reveals that the strong bonding in the Rh-Zr and Rh-Rh or Zr-Zr interaction chains accounts for the structural stability of ortho-RhZr and the hybridization between Rh-4d states and Zr-4d states is strong.
文摘An investigation of electronic property and high pressure phase stability of SmN has been conducted using first principles calculations based on density functional theory. The elec- tronic properties of Stun show a striking feature of a half metal, the majority-spin electrons are metallic and the minority-spin electrons are semiconducting. It was found that Stun undergoes a pressure-induced phase transition from NaCl-type （B1） to CsCl-type structure （B2） at 117 GPa. The elastic constants of Stun satisfy Born conditions at ambient pressure, indicating that B1 phase of SmN is mechanically stable at 0 GPa. The result of phonon spectra shows that B1 structure is dynamically stable at ambient pressure, which agrees with the conclusion derived from the elastic constants.
基金supported from the National Natural Science Foundation of China(No.51401221,51622401 and 51628402)support from the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB06050100)
文摘The microstructure evolution and phase composition of an α+β titanium alloy, Ti-3Al-5Mo-4.5V(wt.%),have been investigated. Electron probe micro analysis(EPMA) quantitative results manifest that the stability of β phase decreases with increasing quenching temperature, which is influenced by the significant variation of β-stabilizing elements concentration. Detailed microstructure analysis shows that the β→ωphase transformation does occur when quenching at 750℃ and 800 ℃. The ω-reflections change from incommensurate ω-spots(750 ℃) to ideal ω-spots(800 ℃) as the β stability of the alloy decreases. Further the decrease of β phase stability encourages the formation of athermal α " martensite, which has the following orientation relationships: [111]β//[110]α",[100]p//[100]α " and [-110]p//[00-1]α" with respect to the β matrix.
基金This work was financially supported by the National Natural Science Foundation of China(No.51401036)the Hunan Provincial Natural Science Foundation of China(No.14JJ3086),the Research Foundation of Education Bureau of Hunan Province(No.12B001)the Key Laboratory of Efficient and Clean Energy Utilization,College of Hunan Province(No.2015NGQ005).
文摘The phase stability,elastic properties and electronic structures of three typical Mg-Y intermetallics including Mg_(24)Y_(5),Mg_(2)Y and MgY are systematically investigated using first-principles calculations based on density functional theory.The optimized structural parameters including lattice constants and atomic coordinates are in good agreement with experimental values.The calculated cohesive energies and formation enthalpies show that either phase stability or alloying ability of the three intermetallics is gradually enhanced with increasing Y content.The single-crystal elastic constants C_(ij) of Mg-Y intermetallics are also calculated,and the bulk modulus B,shear modulus G,Young's modulus E,Poisson ratio v and anisotropy factor A of polycrystalline materials are derived.It is suggested that the resistances to volume and shear deformation as well as the stiffness of the three intermetallics are raised with increasing Y content.Besides,these intermetallics all exhibit ductile characteristics,and they are isotropic in compression but anisotropic to a certain degree in shear and stiffness.Comparatively,Mg_(24)Y_(5) presents a relatively higher ductility,while MgY has a relatively stronger anisotropy in shear and stiffness.Further analysis of electronic structures indicates that the phase stability of Mg-Y intermetallics is closely related with their bonding electrons numbers below Fermi level.Namely,the more bonding electrons number below Fermi level corresponds to the higher structural stability of Mg-Y intermetallics.
基金supported by the National Natural Science Foundation of China(No.51401221,51622401 and 51628402)the support from the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB06050100)
文摘Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenching temperature variation from dual α+β field(700℃) to single β field(880℃). Tensile tests at ambient temperature show that apparent yield strength of the alloy experiences an abrupt decrease followed by a significant increase from 700℃ to 880℃. Work hardening behavior is characterized by transition from the initial two-regime feature to the three-stage outlook. Concurrently, the maximum working hardening rate drops from 14000 MPa to 3000 MPa, which is concurrent with the shrinking volume fraction of primary a phase. Detailed discussion about the relationship between deformation mechanisms and β phase stability has been outlined.
文摘Two experimental single crystal superalloys, the Ru-free alloy and the Ru-containing alloy with [001 ] orientation, were cast in a directionally solidified furnace, while other alloying element contents were kept unchanged. The effects of Ru on the microstructure and phase stability of the single crystal superalloy were investigated, y＇ directional coarsening and rafting were observed in the Ru-free alloy and Ru-containing alloy after long-term aging at 1070~C for 800 h. Needle-shaped o topologically close packed （TCP） phases precipitated and grew along the fixed direction in both the alloys. The precipitating rate and volume fraction of TCP phases decreased significantly by adding Ru. The compositions ofy and y＇ phases measured using an energy-dispersive X-ray spectroscope （EDS） in transmission electron microscopy （TEM） analysis showed that the addition of Ru lessened the partition ratio of TCP forming elements, Re, W and Mo, and decreased the satu- ration degrees of these elements in y phase, which can enable the Ru-containing alloy to be more resistant to the formation of TCP phases. It is indicated that the addition of Ru to the Ni-based single crystal superalloy with high content of the refractory alloying element can enhance phase stability.
基金Funded by the National Natural Science Foundation of China(No50078019)
文摘Formation, solution and phase change of hydration products in MgO-MgCl2-H2O system was studied with thermodynamics method, and resistance to water immersion and phase change of magnesium oxychloride cement with different MgO/MgCl2 molar ratio was experimented. The results show that pH value of immersion solution of cement paste has a remarkable influence on phase stability of hydration products. A higher pH value leads to a lower solubility and a better phase stability of hydration products. When the solution pH value is higher than 10.37, the precipitation of much Mg（OH）2 crystal induces a worse phase stability of hydration products. With the increasing MgO/MgCl2 molar ratio （lower than 6）, the more amount of MgO in the hydration products enhances the alkalinity of solution and the phase stability is improved. However, when the MgO/MgCl2 molar ratio is higher than 6 and the excessive MgO exsits in the hydration products, the cement paste may be damaged by the excessive crystallization stress of a great deal of Mg（OH）2 formation.
基金financially supported by the National Natural Science Foundation of China (No.51471025)
文摘In this study, high-entropy films with the compo- sition of NbTiA1SiNx were prepared by a reactive direct current （DC） magnetron sputtering technique, with different nitrogen flow rates （0, 4 and 8 ml.min^-1）. The microstructures and properties were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high-resolution transmission electron microscopy （HRTEM）, nano-indenter and spectrophotometer. All of the as-deposited NbTiA1SiNx films are shown to have an amorphous structure, and the films exhibit high thermal stability up to 700℃. The maximum hardness and modulus values of the films reach 20.5 GPa （4 ml.min-1） and 206.8 GPa （0 ml.min^-l）, respectively. The films exhibit high absorption of the solar energy in the wavelength of 0.3-2.5 pm, which indicates that NbTiA1SiNx nitride film is a potential candidate solar selective absorbing coating for high-temperature photo-thermal conversion in the concentrated solar power project.
基金This work is supported by the Key Technologies Research and Development Program of Liaoning Province(2013201018).
文摘Electronic structure and elastic properties of Al_(2)Y,Al_(3)Y,Al_(2)Gd and Al_(3)Gd phases were investigated by means of first-principles calculations from CASTEP program based on density functional theory(DFT).The ground state energy and elastic constants of each phase were calculated,the formation enthalpy(ΔH),bulk modulus(B),shear modulus(G),Young's modulus(E),Poisson's ratio(ν)and anisotropic coefficient(A)were derived.The formation enthalpy shows that Al_(2)RE is more stable than Al_(3)RE,and Al-Y intermetallics have stronger phase stability than Al-Gd intermetallics.The calculated mechanical properties indicate that all these four intermetallics are strong and hard brittle phases,it may lead to the similar performance when deforming due to their similar elastic constants.The total and partial electron density of states(DOS),Mulliken population and metallicity were calculated to analyze the electron structure and bonding characteristics of the phases.Finally,phonon calculation was conducted,and the thermodynamic properties were obtained and further discussed.
基金financially supported by the National Key Research and Development Program of China(Grant No.2018YFC1902400)the National Natural Science Foundation of China(Grant No.51975582)。
文摘High-temperature structural metals remain in high demand for aerospace aircraft,gas turbine engines,and nuclear power plants.Refractory high-entropy alloys(RHEAs)with superior mechanical properties at elevated temperatures are promising candidates for high-temperature structural materials.In this work,a WTaMoNbTi RHEA with adequate room temperature plasticity and considerable strength at 1600℃was fabricated by vacuum arc-melting.The room temperature fracture strain of the as-cast WTaMoNbTi RHEA was 7.8%,which was about 5.2 times that of the NbMoTaW alloy.The alloy exhibited a strong resistance to high-temperature softening,with a high yield strength of 173 MPa and compressive strength of 218 MPa at 1600℃.The WTaMoNbTi RHEA possessed excellent phase stability in the range of room temperature to 2000℃.The dendritic grains grew into equiaxed grains after compression test at 1600℃due to the dynamic recrystallization process at high temperature.This work presents a promising high-temperature structural material that can be applied at 1600℃.
基金financially supported by the National Natural Science Foundation of China (Nos. 51971216 and 51301171)the National Science and Technology Major Project of China (No. 2017-VI-0018-0090)+1 种基金the fund of State Key Laboratory of Long-life High Temperature Materials (No. DTCC28EE190231)the LiaoNing Revitalization Talents Program (No. XLYC1807038)。
文摘Phase stability and its effect on tensile properties of MAR-M247 alloy have been investigated during thermal exposure at 800–900°C for up to 10,000 h.Detailed investigations reveal that the larger secondaryγ′phase has no obvious growth,but the smaller tertiaryγ′phase obviously coarsens and the coalescence occurs during thermal exposure at 850°C and below.γ′coarsening behavior is consistent with the description of Ostwald ripening theory beforeγ′coalescence.Hf-rich blocky MC carbide shows excellent thermal stability,but Ta-rich script-type MC carbide gradually degenerates via reaction,MC+γ→M_(23)C_(6)+γ′and finally formsγ film around MC and M_(23)C_(6) carbides.With increasing thermal exposure time,the tensile strength decreases.The ductility first increases and then decreases during exposure at 800°C,but it decreases continuously at 900°C.In addition,the ductility keeps almost constant when the exposure time is longer than 5000 h.
基金National Natural Science Foundation of China (50771009, 50731001)National Basic Research Program of China (2010CB631200)Research Fund for the Doctoral Program of Higher Education of China (20070006017)
文摘The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3 mol% Yb2O3 （GYb-YSZ） powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed.
文摘The residual austenite and its stability in commercial 60Si2Mn steel treated by quenching and partitioning(Q-P)were investigated.The Q-P heat treatment was carried out using a system of ordinary electric furnace--oil bath box--electric furnace.Cryogenic treatments at different temperatures were performed to assess the thermal stability of residual austenite.The microstructure,particularly residual austenite,was analyzed using optical microscope and X-ray diffraction(XRD),and the microhardness and Rockwell hardness were measured.The residual austenite with the volume fraction as much as 13.7%and the HRC hardness level of 41 were achieved,and the residual austenite is relatively stable.
基金supported by the 45th China Postdoctoral Science Foundation (Grant No.20090451101)the Xiangtan University Postdoctoral Science Foundation
文摘The characteristic crystal model is applied to the study of phase stability and thermodynamics in substitutional bcc-based Ta-W alloys.The basic principle and method of alloy thermodynamics which is described by the characteristic crystal model is introduced in detail.The Gibbs energy of various phases including both disordered and ordered phases of the Ta-W system are evaluated.The phase diagram of Ta-W alloys is assessed and predicted.The results are in good agreement with experiments and better than that of first principle.
基金financially supported by the National Natural Science Foundation of China(No.51771044)the Natural Science Foundation of Hebei Province(No.E2019501061)+2 种基金the Performance subsidy fund for Key Laboratory of Dielectric and Electrolyte Functional Material Hebei(No.22567627H)the Fundamental Research Funds for the Central Universities(No.N2223025)the Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project of China 2.0,No.BP0719037)。
文摘The phase stability,magnetic properties,martensitic transformation,and electronic properties of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system with excess Mn have been systematically investigated by the first-principles calculations.Results indicate that the excess Mn atoms will directly occupy the sublattices of Ni(MnNi)or Sn(MnSn).The formation energy(Ef)of the austenite has a relationship with the Mn content:Ef=135.27(1+x+y)−293.01,that is,the phase stability of the austenite decreases gradually with the increase in Mn content.According to the results of the formation energy of austenite,there is an antiparallel arrangement of the magnetic moment between the excess and normal Mn atoms in the Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x=0 or y=0)system,while the magnetic moment direction of the normal Mn atoms arranges antiparallel to that of MnNi atoms and parallel to that of MnSn atoms in the Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x,y≠0)system.The martensitic transformation occurs in some Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x,y≠0)alloys with large magnetic moments of ferrimagnetic austenite.Besides,the valence electrons tend to distribute around the Ni or MnNi atoms and mainly bond with the normal Mn atoms.The results of this work can lay a theoretical foundation for further development of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system as the potential ferromagnetic shape memory alloys.
基金financially supported by the National Natural Science Foundation of China(No.51771044)the Natural Science Foundation of Hebei Province(No.E2019501061)+2 种基金the Fundamental Research Funds for the Central Universities(No.N2023027)the Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project of China 2.0,No.BP0719037)the Liao Ning Revitalization Talents Program(No.XLYC1802023)。
文摘The effects of site occupation on the phase stability,martensitic transformation,and the magnetic and electronic properties of a full series of Ni-Mn-In alloys are theoretically studied by using the ab initio calculations.Results indicate that the excess atoms of the rich component directly take the sublattices of the deficient components of the Ni2Mn_(1+x)In_(1-x),Ni2-xMn_(1+x)In,and Ni_(2+x)Mn_(1-x)In alloys.Nevertheless,the mixed and indirect site occupations may coexist in the Ni_(2+x)Mn In_(1-x)system.The relevant magnetic configurations of the austenite for the four alloy systems have also been determined.The results show that,except for the austenite in the Ni2-xMn_(1+x)In alloys,which tend to be ferrimagnetic,the other alloys all present ferromagnetic austenite.Thus,the site occupation and associated magnetic states are the crucial influencing factors of the phase stability,martensitic transformation,and the total magnetic moment.The electronic structure of the austenite phase also shows that the covalent bonding plays an important role in the phase stability.The key finding of this work is both Ni2Mn_(1+x)In_(1-x)and Ni_(2+x)Mn In_(1-x)alloys serve as the potential shape memory alloys.
基金financially supported by the National Natural Science Foundation of China(Grant No.51771044)the Natural Science Foundation of Hebei Province(No.E2019501061)+2 种基金the Fundamental Research Funds for the Central Universities(No.N2023027)the Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project of China 2.0,No.BP0719037)the LiaoNing Revitalization Talents Program(Grant No.XLYC1802023)。
文摘The all-d-metal Ni-Mn-Ti Heusler alloy has giant elastocaloric eff ect and excellent mechanical properties,which is diff erent from the conventional Ni-Mn-based Heusler alloys.In this work,the preferred site occupation,phase stability,martensitic transformation,magnetic properties,and electronic structure of the B-doped Ni_(2)Mn_(1.5)Ti_(0.5)alloys are systematically investigated by the fi rst-principles calculations.The results show that B atoms preferentially occupy the octahedral interstitial.The doped B atoms tend to exist in the(Ni_(2)Mn_(1.5)Ti_(0.5))_(1-x)B_(x)(x=0.03,0.06,0.09)alloy in the form of aggregation distribution,and the martensitic transformation temperature decreases with the increase in the B content.For octahedral interstitial doping,the toughness and plasticity of the(Ni_(2)Mn_(1.5)Ti_(0.5))_(1-x)B_(x) alloys decrease,but the strength and rigidity are greatly enhanced.This is because a small part of the d-d hybridization in ternary Ni-Mn-Ti alloy is replaced by the p-d hybridization in Ni-Mn-Ti-B alloy.
