Unraveling indentation-induced slip steps in austenitic stainless steel
Unraveling indentation-induced slip steps in austenitic stainless steel
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DOI：
10.1016/j.matdes.2019.108169
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发表时间：
2019-12
影响因子：
8.4
通讯作者：
Wenzhen Xia;G. Dehm;S. Brinckmann
中科院分区：
文献类型：
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作者：
Wenzhen Xia;G. Dehm;S. Brinckmann
在过去的几十年里，纳米压痕技术被广泛地用于在微观尺度上实验表征相的弹性和塑性材料特性。伴随的模拟研究了纳米压痕过程中的塑性机制。虽然实验和模拟已经导致在纳米压痕的大多数机制的透彻理解，塑性的正和负倾斜的滑移面仍然不完全清楚。在这项工作中，{1 0 0}-，{1 0 1}-和{1 1 1}-奥氏体不锈钢晶粒缩进，以更好地了解位错介导的塑性通过滑移台阶分析。我们观察到，滑动发生在正，负倾斜的滑移面在纳米压痕，我们提出的方法来区分这两种类型的平面。我们发现，正倾斜的滑移面上的滑移台阶形成优先在早期阶段相比，形成的负倾斜的滑移台阶，这发生在后期变形阶段，由于表面形貌的变化。通过计算存在和不存在堆积时的分解剪应力，揭示了正、负斜面上滑移的起源以及出现顺序的原因。我们的结论是，占在实验和模拟的表面形貌的演变是必不可少的预测在纳米压痕过程中的塑性滑移激活。
Nanoindentation has been used intensively during the last decades to characterize experimentally the elastic and plastic material properties of phases at the microscale. Accompanying simulations have investigated the plastic mechanisms during nanoindentation. While experiments and simulations have led to a thorough understanding of most mechanisms during nanoindentation, the plasticity on positively and negatively inclined slip planes is still not completely clear. In this work, {1 0 0}-, {1 0 1}- and {1 1 1}-grains of an austenitic stainless steel are indented to better understand the dislocation mediated plasticity through slip step analysis. We observe that slip occurs on positively and negatively inclined slip planes during nanoindentation and we propose methods to differentiate between both types of planes. We find that slip steps on positively inclined slip planes form preferentially during the early stage as compared to the formation of slip steps on negative inclination, which occurs during the later deformation stage due to the change in surface topography. By calculating the resolved shear stress in the presence and absence of pile-ups, we reveal the origin of slip on positively and negatively inclined planes as well as the reason for the sequence of occurrences. We conclude that accounting for the surface topography evolution in experiments and simulations is essential in predicting the plastic slip activation during nanoindentation.