Ti掺杂对高熵合金FeCrVMoTi_(x)(x=0-1)结构和力学性能的影响

Effect of Ti doping on the structural and mechanical properties of FeCrVMoTi_(x)(x=0-1)

采用第一性原理方法研究了Ti对高熵合金FeCrVMoTi_(x)结构、弹性和塑性的影响.分别用混合焓、原子尺寸差、价电子浓度、相对熵效应和结合能评价FeCrVMoTi_(x)结构的稳定性,研究发现BCC型的FeCrVMoTi_(x)在x=0.0-0.9范围内都是结构稳定的.另外,弹性和塑性的计算发现,块体模量随Ti的增加而线性减小.剪切模量和杨氏模量首先随x的增加而变大,然后达到最大值,最后随x的进一步增加而快速减小.Ti的掺杂有助于提高FeCrVMoTi_(x)的屈服强度和抗拉强度,其中FeCrVMoTi_(0.57)的拉伸性能最好.热力学的计算表明压强能够抑制FeCrVMoTi_(0.57)的体膨胀系数,并增强其德拜温度.

The first-principles method is applied to investigate the alloying effect of Ti on structural stability,elastic and plastic properties of FeCrVMoTi_(x)high entropy alloys.The mixing enthalpy,atomic size difference,valence-electron concentration,relative entropy effect and cohesive energies are employed to evaluate structure stability of FeCrVMoTi_(x),and it is found that BCC FeCrVMoTi_(x)is stable at the range of x=0.0-0.9.Furthermore,the elastic and plastic property calculations show the bulk modulus almost decreases linearly with the increasing Ti content.The shear modulus and Young’s modulus firstly increases with the increasing x,and then both reach maximum values.Finally,they decrease rapidly with the further increase of Ti.The Ti-doping would increase the yield strength and the tensile strength of FeCrVMo,and FeCrVMoTi_(0.57)has better performance.The thermodynamic calculates show that the pressure has a suppressed effect on the volume expansion coefficient of FeCrVMoTi_(0.57)but an enhanced effect on its Debye temperature.