Phase field study of the microstructure evolution and thermomechanical properties of polycrystalline shape memory alloys: Grain size effect and rate effect
Phase field study of the microstructure evolution and thermomechanical properties of polycrystalline shape memory alloys: Grain size effect and rate effect
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DOI：
10.1016/j.commatsci.2018.01.014
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发表时间：
2018-04
影响因子：
3.3
通讯作者：
Yuanzun Sun;Jun Luo;Jingming Zhu
中科院分区：
文献类型：
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作者：
Yuanzun Sun;Jun Luo;Jingming Zhu
形状记忆合金（SMA）是一类金属智能材料，具有伪弹性（PE）和形状记忆效应（SME），具体取决于环境温度。 SMA 独特的热机械性能源于温度诱导以及应力诱导的马氏体转变 (MT)。先前的研究工作表明，多晶 SMA 的热机械性能取决于晶粒尺寸和速率。为了探索这种现象背后的物理机制，本文开发了相场（PF）模型来研究动态载荷下多晶 SMA 的微观结构演变和热机械响应。同时考虑相变过程中的惯性效应、潜热释放和传导。 PF 模型还考虑了相变过程中晶界能量的变化。然后进行数值模拟来研究温度引起的 MT 以及不同晶粒尺寸的纳米晶 SMA 的应力引起的马氏体重新取向。系统讨论了晶粒尺寸、潜热效应和加载速率对微观结构演化过程和应力应变曲线的影响。
Shape memory alloys (SMAs) are a class of metallic smart materials which possess pseudoelasticity (PE) and shape memory effect (SME), depending on the ambient temperature. The unique thermomechanical properties of SMAs originate from the temperature-induced as well as stress-induced martensitic transformations (MTs). Former research work has shown that the thermomechanical properties of polycrystalline SMAs are grain size and rate dependent. In order to explore the physical mechanisms behind this phenomenon, a phase field (PF) model is developed in this paper to study the microstructure evolution and the thermomechanical responses of polycrystalline SMAs under dynamic loadings. The inertial effect, the latent heat release and conduction during the phase transformation are simultaneously considered. The grain boundary energy change during the phase transformation is also accounted for in the PF model. Numerical simulations are then conducted to study the temperature-induced MT as well as the stress-induced martensite reorientation of nanocrystalline SMAs with different grain sizes. The influences of the grain size, the latent heat effect and the loading rate on the microstructure evolution process and the stress–strain curves are systematically discussed.