FeCoCrCuNi高熵合金裂纹及孔洞结构力学与微观构象演化机理的分子动力学模拟研究

本文采用分子动力学方法研究了FeCoCrCuNi高熵合金裂纹及孔洞模型结构在不同轴向拉伸应变速率下的力学与微观结构演化机理. 结果表明：应变速率越高FeCoCrCuNi裂纹结构对应更高的过冲应变和过冲应力，其主要原因是高拉伸速率会导致高强度的BCC结构及孪晶结构的生成，而BCC结构及孪晶结构的产生进而会抑制应力的下降，通过应力-应变曲线，可知FeCoCrCuNi裂纹模型在轴向应力作用下表现为塑性形变. 对于不同尺寸的孔洞FeCoCrCuNi裂纹模型的应力模拟与结构分析，可以得出：孔洞尺寸越大, FeCoCrCuNi裂纹结构对应的过冲应变和过冲应力越小，其主要原因是大尺寸的孔洞造成孔洞之间产生裂纹的，进而会影响这个材料的屈服应变和屈服强度.

Study on the mechanical performance and microstructure of FeCoCrCuNi high-entropy alloy with crack and void by molecular dynamics simulations

Molecular dynamics (MD) simulations have used to study the mechanical performance and microstructure of FeCoCrCuNi high-entropy alloy with crack and void. The MD simulation results have shown that higher uniaxial stretched rate corresponding higher overshoot stress and strain. This is due to the generation of BCC and twin crystal structure in FeCoCrCuNi model with high stretched rate. And the BCC and twin crystal structure will slow down the decrease of the stress. Thus, FeCoCrCuNi is plastic deformation under uniaxial stretched deformation. For voided-FeCoCrCuNi high-entropy alloy, the MD results shown that the values of the overshoot stress and strain are decreasing with the increase of the size of void. This is due to the generation of the crack between the voids for FeCoCrCuNi high-entropy alloy.