Abstract Unusual orientation-dependent mechanical responses during nanoindentations of nickel-titanium shape-memory alloys are studied by performing a series of large-scale molecular dynamics simulations. By analyzing the mechanical responses of single crystal nickel-titanium shape-memory alloys during indentations along [1 1 1] and [0 0 1] directions, the present study provides direct supporting results emphasizing the importance of the anisotropy in the martensite formation. The microstructural evolution, especially for the martensitic transformation beneath the indenter tip, is clearly visualized and directly related to the indentation load-depth curves and the surface profile. The results show that the reported orientation-dependency of the indentation load-depth curves is decisively driven by the anisotropy in the preferred growth direction of the martensite phase and the amount of the martensite phase formed beneath the indenter tip.

中文翻译：

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NiTi形状记忆合金纳米压痕过程中取向相关马氏体转变的原子模拟

摘要 通过执行一系列大规模分子动力学模拟，研究了镍钛形状记忆合金纳米压痕过程中与取向相关的异常机械响应。通过分析单晶镍钛形状记忆合金在沿 [1 1 1] 和 [0 0 1] 方向压痕时的机械响应，本研究提供了直接的支持结果，强调了各向异性在马氏体形成中的重要性。显微组织演变，特别是压头尖端下方的马氏体转变，清晰可见，并与压痕载荷-深度曲线和表面轮廓直接相关。