Abstract An austenite-martensite phase boundary in shape memory alloys (SMA) is associated with a periodic microstructure of martensite twin lamellas. Microscopy studies show that the period, which represents the thickness of the twin lamellas, increases with the distance from the habit plane. This observation is often overlooked when the microstructure and energy of the austenite-martensite interface are evaluated. In this paper we introduce a model that reproduces the variation in the twin lamella period. For this purpose, the overall energy of the phase boundary and the accompanied twinned microstructure is formulated and minimized. In particular, the effect of twinning disconnections, via which twins are tapered or broaden, and the additional energy due to the disconnections, are considered. Fittings of model predictions with measurements based on microscopy images provide evaluations of the twin boundary and twinning disconnection energies. Comparison of the results with expressions based on the theory of dislocations indicates that interactions between disconnections play a dominant role in determining the overall energy of twinning disconnections.

中文翻译：

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形状记忆合金中奥氏体-马氏体相界和孪晶组织的分析：孪晶断开的作用

摘要 形状记忆合金 (SMA) 中的奥氏体-马氏体相界与马氏体孪晶的周期性微观结构有关。显微镜研究表明，代表双薄片厚度的周期随着距习性平面的距离而增加。在评估奥氏体-马氏体界面的微观结构和能量时，这一观察结果常常被忽视。在本文中，我们介绍了一个模型，该模型再现了双薄片时期的变化。为此，相界和伴随的孪晶微观结构的总能量被制定并最小化。特别地，考虑了孪生断开的影响，孪生通过其逐渐变细或变宽，以及由于断开而产生的额外能量。模型预测与基于显微镜图像的测量的拟合提供了对孪晶边界和孪晶断开能量的评估。结果与基于位错理论的表达式的比较表明，断开之间的相互作用在确定孪生断开的总能量中起主导作用。