Abstract The reverse martensitic transformation proceeds through several sub-processes at various length and time scales. We study the transformation kinetics at the high thermodynamic driving force regime, by inducing a rapid heating-pulse in a shape memory alloy wire. We track the evolution of the transformation at the microsecond scale by multi-frame time-resolved X-ray diffraction at synchrotron radiation with simultaneous high-bandwidth force measurements. The x-ray probed a narrow region at the periphery of the wire, while the force was a measure for the transformation-induced stress in the bulk of the wire. We reveal three stages occurring at different times and length-scales in the material. During the first 5 μs the transformation is undetectable. Then, a rapid transformation occurs near the surface and saturates after 9 μs. The evolution of the transformation in the bulk becomes discernible only after the transformation near the surface completes and lasts for approximately 40 μs.

中文翻译：

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高驱动力状态下马氏体转变的演变：微秒级时间分辨 X 射线衍射研究

摘要 逆马氏体相变通过不同长度和时间尺度的几个子过程进行。我们通过在形状记忆合金线中诱导快速加热脉冲来研究高热力学驱动力状态下的转变动力学。我们通过同步加速器辐射的多帧时间分辨 X 射线衍射和同步高带宽力测量来跟踪微秒级转换的演变。X 射线探测了金属丝外围的一个狭窄区域，而力则是测量金属丝主体中由相变引起的应力的量度。我们揭示了材料中在不同时间和长度尺度上发生的三个阶段。在前 5 μs 期间，无法检测到转换。然后，在表面附近发生快速转变并在 9 μs 后饱和。