During the ferrite-to-austenite transformation, the accommodation of the volume misfit between ferrite and austenite induces strain localization in both phases. A detailed understanding of this mechanism is a necessary step towards the improvement of thermomechanical treatments of iron alloys. Full-field measurements of displacement during heating of high purity iron samples are thoroughly post-processed to track the transformation in situ. They allow a fine characterization of the interaction between local plastic events and microstructure evolutions during the transformation. The deformation of austenite grains bears strong signatures in terms of orientation that can be used to monitor their individual growth in temperature. The parent phase acts as an elastoplastic matrix embedding an inclusion everywhere except at grain boundaries where additional localizations induced by crystal rotations precede the transformation interface.

在铁素体到奥氏体的转变过程中，铁素体和奥氏体之间体积失配的调节会在两个相中引起应变局部化。对这种机理的详细了解是改进铁合金热机械处理的必要步骤。对高纯度铁样品加热期间位移的全场测量进行了彻底的后处理，以跟踪原位转变。它们可以很好地表征转变过程中局部塑性事件与微观结构演变之间的相互作用。奥氏体晶粒的变形在取向方面具有很强的特征，可用于监测其温度的个体增长。母相充当弹塑性基质，将嵌入物嵌入到各处，但在晶界处除外，在晶界处，由晶体旋转引起的其他局部化位于相变界面之前。