Abstract The selection of crystallographic variants in bainitic microstructures is a deeply studied topic which can be attributed to several reasons. In the cases where the prior austenite is textured, stressed or plastically deformed, the final ferrite texture and the dilatometry signal may change, being anisotropic. Although the causality between variant selection and the variation of the dilatometric signal has been previously assumed, it has not been thoroughly proved. In this work, the phenomenological theory of martensite was combined with a continuum mechanics analysis to calculate the relative length changes associated to the bainitic transformation during different bainitic transformations in order to prove the connection between the selection of crystallographic variants and the distortion of the dilatometry signal. To do so, four different bainitic microstructures were analyzed: one of them obtained by a pure isothermal treatment and the rest of them obtained by ausforming treatments. Some of the mentioned microstructures had shown to lead to negative longitudinal dilatometry signals and to present a strong variant selection. Results showed that the experimental trends could be explained by theoretical means, which enables to further understand the bainitic transformation.

中文翻译：

---

解释变体选择作用下贝氏体转变过程中的膨胀行为

摘要 贝氏体显微组织中结晶变体的选择是一个深入研究的课题，其原因有很多。在原奥氏体发生织构、应力或塑性变形的情况下，最终铁素体织构和膨胀测量信号可能会发生变化，呈各向异性。尽管先前已经假设了变体选择与膨胀信号变化之间的因果关系，但尚未得到彻底证明。在这项工作中，马氏体的唯象理论与连续介质力学分析相结合，计算了不同贝氏体转变过程中与贝氏体转变相关的相对长度变化，以证明晶体变体的选择与膨胀测量信号失真之间的联系。 . 为此，分析了四种不同的贝氏体显微组织：其中一种是通过纯等温处理获得的，而其余的则是通过奥氏成形处理获得的。一些提到的微结构已显示导致负纵向膨胀测量信号并呈现出强烈的变体选择。结果表明，实验趋势可以用理论方法解释，从而可以进一步了解贝氏体转变。