Abstract Localized heat treatments via Joule effect were performed on cold-drawn NiTi strips to produce a functionally graded material (FGM). Three zones where locally heat treated at 300, 350, and 400 °C for 10 min followed by air cooling. Multiscale and multiphenomena characterization of the obtained FGM was performed through infrared temperature testing, four-point probe and eddy current testing, mechanical testing and synchrotron X-ray diffraction. The effect of these localized heat treatments is clearly observed by different techniques. The use of these short and localized heat treatments avoids the need of highly expensive manufacturing routes typically used to obtain the same effect on NiTi shape memory alloys, thus opening new possibilities for processing these advanced engineering alloys.

中文翻译：

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基于焦耳效应的功能梯度 NiTi 形状记忆合金的制备和表征

摘要 通过焦耳效应对冷拔镍钛带材进行局部热处理以生产功能梯度材料（FGM）。三个区域在 300、350 和 400 °C 下局部热处理 10 分钟，然后进行空气冷却。通过红外温度测试、四点探针和涡流测试、机械测试和同步加速器 X 射线衍射对获得的 FGM 进行多尺度和多现象表征。通过不同的技术可以清楚地观察到这些局部热处理的效果。这些短时间和局部热处理的使用避免了通常用于在 NiTi 形状记忆合金上获得相同效果的非常昂贵的制造路线的需要，从而为加工这些先进的工程合金开辟了新的可能性。