Zhou Jinjie, He Yingle, Shen Jinchuan, Essa F A, Yu Jingui
School of Mechanical Engineering, North University of China, Taiyuan, 030051, People's Republic of China.
School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan, 430070, People's Republic of China.
Nanotechnology. 2021 Dec 13;33(10). doi: 10.1088/1361-6528/ac3d62.
Nickel-based single crystal alloys have excellent mechanical properties due to its unique two-phase structure and interface. Therefore, molecular dynamics methods were used to simulate nanoindentation and microstructural evolution. We found the indenter reaction force and hardness of the NiAl phase is the largest. The pop-in event in NiAl phase is more obvious than that in the Ni phase and Ni/NiAl phase. Because lots of dislocations in the NiAl phase break through the barrier of the interface and cut into the Ni phase, while dislocations in the Ni phase only slip inside the Ni phase. Moreover, we found that the position of the starting point of the adhesion force recovery is mainly related to the elastic recovery of the material. The stronger the elastic recovery of the phase, the smaller the depth value corresponding to the starting point of the recovery. We further studied the variation of potential energy with indentation depth and found that the change of wave trough of the load-displacement (-) curve is related to stacking fault energy. This study has important theoretical guiding significance for the in-depth understanding and engineering application of the mechanical properties of nickel-based single crystal alloys.
镍基单晶合金因其独特的两相结构和界面而具有优异的力学性能。因此，采用分子动力学方法模拟纳米压痕和微观结构演变。我们发现NiAl相的压头反作用力和硬度最大。NiAl相中的弹出事件比Ni相和Ni/NiAl相中的更明显。因为NiAl相中的大量位错突破界面势垒并切入Ni相，而Ni相中的位错仅在Ni相内部滑移。此外，我们发现粘附力恢复起点的位置主要与材料的弹性恢复有关。相的弹性恢复越强，恢复起点对应的深度值越小。我们进一步研究了势能随压痕深度的变化，发现载荷-位移（-）曲线波谷的变化与堆垛层错能有关。该研究对深入理解镍基单晶合金的力学性能及工程应用具有重要的理论指导意义。
