Iridium(Ir)-based superalloys withγ/γ'twophase microstructure are recognized as next-generation high-temperature materials for aerospace engines operating above 1500℃.The strengthening phases can markedly enhan...Iridium(Ir)-based superalloys withγ/γ'twophase microstructure are recognized as next-generation high-temperature materials for aerospace engines operating above 1500℃.The strengthening phases can markedly enhance the mechanical strength of alloys.However,these phases exhibit significant brittleness,and their properties in Ir-based alloys remain insufficiently investigated.Here,the high-throughput calculations were employed to screen the potentialγ'phases for Ir_(3)X(X=Al,Si,Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Y,Zr,Nb,Mo,Tc,Ru,Rh,Pd,Ag,Cd,La,Hf,Ta,W,Re,Os,Pt,Au,Th)through systematic assessment of phase stability,melting points,shear modulus and anti-phase boundary(APB)energies.Subsequently,lattice misfit was further optimized through thirdelement compositional design in Ir_(3)(Ti_(0.5)X_(0.5))(X=Nb,Hf,Zr,Ta).The dependence of yield strength on precipitate size was systematically evaluated through the precipitation strengthening effect.Ir_(3)(Ti_(0.5)Ta_(0.5))displays a reduced lattice misfit(0.63%),accompanied by a higher shear modulus(207 GPa),elevated APB energy(920 mJ m^(-2)),and an increased Poisson's ratio(0.25),demonstrating a synergistic improvement in these interrelated mechanical characteristics.The increase of density of states value at Fermi level and the right-shift of the peak in the bonding region result in the improved ductility.The greatest delocalization degree of electrons around Ta and the shorter Ir-Ta bond lengths are responsible for its higher shear modulus and APB energies.A novel Ir_(3)(Ti_(0.5)Ta_(0.5))composition balancing the trade-off between high strength and ductility is expected to guide the development of Irbased superalloys.展开更多
The mechanical,thermodynamic properties and electrical conductivities of L1_(2)-Al_(3)X(X=Zr,Sc,Er,Yb,Hf)structural phases in aluminum conductors were investigated through a first-principles study.The results demonstr...The mechanical,thermodynamic properties and electrical conductivities of L1_(2)-Al_(3)X(X=Zr,Sc,Er,Yb,Hf)structural phases in aluminum conductors were investigated through a first-principles study.The results demonstrate that all structural phases have good alloy-forming ability and structural stability,where Al_(3)Zr is the most superior.Al_(3)Zr,Al_(3)Hf and Al_(3)Sc have enhanced shear and deformation resistance in comparison to other phases.Within the temperature range of 200−600 K,Al_(3)Er and Al_(3)Yb possess the greatest thermodynamic stability,followed by Al_(3)Hf,Al_(3)Zr and Al_(3)Sc.Al_(3)Er and Al_(3)Yb have higher thermodynamic stability than Al_(3)Hf,Al_(3)Zr and Al_(3)Sc.All structural phases exhibit substantial metallic properties,indicating their good electrical conductivity.The electrical conductivities of Al_(3)Hf and Al_(3)Zr are higher than those of Al_(3)Er,Al_(3)Yb and Al_(3)Sc.The covalent bond properties in Al_(3)Sc,Al_(3)Er and Al_(3)Yb enhance the hardness,brittleness and thermodynamic stability of the structural phase.The thermodynamic stability of Al_(3)Sc is significantly reduced by ionic bonds.展开更多
The structure,stability and elastic properties of di-transition-metal carbides TixV1-xC were investigated by using the first-principles with a pseudopotential plane-waves method.The results show that the equilibrium l...The structure,stability and elastic properties of di-transition-metal carbides TixV1-xC were investigated by using the first-principles with a pseudopotential plane-waves method.The results show that the equilibrium lattice constants of TixV1-xC show a nearly linear reduction with increasing addition of V.The elastic properties of TixV1-xC are varied by doping with V.The bulk modulus of Ti0.5V0.5C is larger than that of pure TiC,as well as Ti0.5V0.5C has the largest C44 among TixV1-xC（0≤x≤1）,indicating that Ti0.5V0.5C has higher hardness than pure TiC.However,Ti0.5V0.5C presents brittleness based on the analysis of ductile/brittle behavior.The Ti0.5V0.5C carbide has the lowest formation energy,indicating that Ti0.5V0.5C is more stable than all other alloys.展开更多
基金financially supported by the Major R&D Project of Yunnan Province(Nos.202302AB080021 and 202402AB080007)the Major R&D Project of Yunnan Precious Metals Laboratory Co.,Ltd.(No.YPML-2023050205)+1 种基金Yunnan Major Research and Development Plan(No.202403AA080016)the Open Project of Yunnan Precious Metals Laboratory Co.,Ltd.(No.YPML-20240502066)
文摘Iridium(Ir)-based superalloys withγ/γ'twophase microstructure are recognized as next-generation high-temperature materials for aerospace engines operating above 1500℃.The strengthening phases can markedly enhance the mechanical strength of alloys.However,these phases exhibit significant brittleness,and their properties in Ir-based alloys remain insufficiently investigated.Here,the high-throughput calculations were employed to screen the potentialγ'phases for Ir_(3)X(X=Al,Si,Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Y,Zr,Nb,Mo,Tc,Ru,Rh,Pd,Ag,Cd,La,Hf,Ta,W,Re,Os,Pt,Au,Th)through systematic assessment of phase stability,melting points,shear modulus and anti-phase boundary(APB)energies.Subsequently,lattice misfit was further optimized through thirdelement compositional design in Ir_(3)(Ti_(0.5)X_(0.5))(X=Nb,Hf,Zr,Ta).The dependence of yield strength on precipitate size was systematically evaluated through the precipitation strengthening effect.Ir_(3)(Ti_(0.5)Ta_(0.5))displays a reduced lattice misfit(0.63%),accompanied by a higher shear modulus(207 GPa),elevated APB energy(920 mJ m^(-2)),and an increased Poisson's ratio(0.25),demonstrating a synergistic improvement in these interrelated mechanical characteristics.The increase of density of states value at Fermi level and the right-shift of the peak in the bonding region result in the improved ductility.The greatest delocalization degree of electrons around Ta and the shorter Ir-Ta bond lengths are responsible for its higher shear modulus and APB energies.A novel Ir_(3)(Ti_(0.5)Ta_(0.5))composition balancing the trade-off between high strength and ductility is expected to guide the development of Irbased superalloys.
基金National Natural Science Foundation of China (No. 52274403)。
文摘The mechanical,thermodynamic properties and electrical conductivities of L1_(2)-Al_(3)X(X=Zr,Sc,Er,Yb,Hf)structural phases in aluminum conductors were investigated through a first-principles study.The results demonstrate that all structural phases have good alloy-forming ability and structural stability,where Al_(3)Zr is the most superior.Al_(3)Zr,Al_(3)Hf and Al_(3)Sc have enhanced shear and deformation resistance in comparison to other phases.Within the temperature range of 200−600 K,Al_(3)Er and Al_(3)Yb possess the greatest thermodynamic stability,followed by Al_(3)Hf,Al_(3)Zr and Al_(3)Sc.Al_(3)Er and Al_(3)Yb have higher thermodynamic stability than Al_(3)Hf,Al_(3)Zr and Al_(3)Sc.All structural phases exhibit substantial metallic properties,indicating their good electrical conductivity.The electrical conductivities of Al_(3)Hf and Al_(3)Zr are higher than those of Al_(3)Er,Al_(3)Yb and Al_(3)Sc.The covalent bond properties in Al_(3)Sc,Al_(3)Er and Al_(3)Yb enhance the hardness,brittleness and thermodynamic stability of the structural phase.The thermodynamic stability of Al_(3)Sc is significantly reduced by ionic bonds.
基金Project(Z2006F07)supported by Natural Science Foundation of Shandong Province,China
文摘The structure,stability and elastic properties of di-transition-metal carbides TixV1-xC were investigated by using the first-principles with a pseudopotential plane-waves method.The results show that the equilibrium lattice constants of TixV1-xC show a nearly linear reduction with increasing addition of V.The elastic properties of TixV1-xC are varied by doping with V.The bulk modulus of Ti0.5V0.5C is larger than that of pure TiC,as well as Ti0.5V0.5C has the largest C44 among TixV1-xC（0≤x≤1）,indicating that Ti0.5V0.5C has higher hardness than pure TiC.However,Ti0.5V0.5C presents brittleness based on the analysis of ductile/brittle behavior.The Ti0.5V0.5C carbide has the lowest formation energy,indicating that Ti0.5V0.5C is more stable than all other alloys.
