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利用分子动力学方法分别模拟金刚石压头压入Ni模型和Ni基单晶合金γ/γ′模型的纳米压痕过程,通过计算得到两种模型[001]晶向的弹性模量及硬度.采用中心对称参数分析不同压入深度时两种模型内部位错形核、长大过程以及Ni基单晶合金γ/γ′(001)相界面错配位错对纳米压痕过程的影响.结果显示:压入深度0.641 nm之前,两种模型的压入载荷-压入深度曲线相似,说明此时相界面处的错配位错对纳米压痕过程的影响很小;压入深度0.995 nm时,在错配位错处发生位错形核,晶体在γ相中沿着{111}面滑移,随即导致Ni基单晶合金γ/γ′模型压入载荷的下降,并在压入深度达到1.487 nm之前低于Ni模型相同压入深度时的压入载荷;压入深度从1.307 nm开始,由于相界面错配位错的阻碍作用,Ni基单晶合金γ/γ′模型压入载荷上升速度较快.
Molecular dynamics simulation was used to simulate the nanoindentation process of Ni / Ni alloy and Ni / Ni single crystal alloy γ / γ ’respectively. The elastic modulus and hardness of [001] crystal orientation were obtained by calculation. Center symmetry parameters were used to analyze the effect of dislocation nucleation and growth process and the mismatch dislocation at γ / γ ’(001) phase interface on the nanoindentation process at different depths of indentation.The results show that The results show that the mismatch dislocations at the phase interface have little effect on the nanoindentation process before the depth of 0.641 nm is pressed in. When the depth of penetration is 0.995 nm, Dislocation nucleation occurs at the mismatch dislocation, and the crystal slides along the {111} plane in the γ phase, which leads to the decrease of the press-in load of the γ / γ ’Ni-based single crystal alloy. When the indentation depth reaches 1.487 nm was lower than that of the Ni model at the same penetration depth. Starting from 1.307 nm, the γ / γ ’model of the Ni-based single crystal alloy was pressed into the ascending rate of loading due to the obstruction of mismatch dislocation at the phase interface. Faster.