Instrumented indentation has proved to be an invaluable tool to determine the small volume mechanical behaviour of shape memory alloys (SMAs). Multi-axial experiments show that SMAs can exhibit pressure sensitive martensite phase transformation, which manifests in terms of tension-compression asymmetry of the associated stress and strain. Since high magnitude of pressure can prevail during indentation, the spherical indentation response of SMAs is investigated in this work by using a constitutive model that captures the above behaviour. Finite element (FE) simulations are first performed at two temperatures (close to A s and above A f ) and corresponding to different values of pressure sensitivity parameter γ 1 for a Ni-Ti SMA. It is found that the indentation load and mean contact pressure enhance at a given depth, while the residual depth at complete unloading (for temperature below A f ...

中文翻译：

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压力敏感性对形状记忆合金球形压痕响应的影响

事实证明，仪器压痕是确定形状记忆合金（SMA）的小体积力学行为的宝贵工具。多轴实验表明，SMA可以表现出压敏马氏体相变，这表现为相关应力和应变的拉压不对称性。由于压痕过程中可能会出现较大的压力，因此在这项工作中，通过使用捕获上述行为的本构模型来研究SMA的球形压痕响应。首先在两个温度下（接近A s且高于A f）并分别对应于Ni-Ti SMA的压力敏感度参数γ1的不同值进行有限元（FE）模拟。发现在给定深度，压痕载荷和平均接触压力会增加，