Effect of laser welding parameters on the austenite and martensite phase fractions of NiTi
Effect of laser welding parameters on the austenite and martensite phase fractions of NiTi
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DOI：
10.1016/j.matchar.2016.08.001
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发表时间：
2016-09-01
影响因子：
4.7
通讯作者：
Ocana, J. L.
中科院分区：
文献类型：
--
作者：
Oliveira, J. P.;Braz Fernandes, F. M.;Ocana, J. L.
尽管激光焊接可能是 NiTi 形状记忆合金最常用的连接技术，但仍然缺乏对激光焊接参数对微观结构引起的变化的影响的了解：在热影响区和熔融区中可能存在马氏体，而基材完全是奥氏体。同步加速器 X 射线衍射用于精细探测激光焊接镍钛接头。通过 Rietveld 精修，确定了马氏体和奥氏体相分数，并观察到马氏体含量向焊接中心线方向增加。这与这些区域的局部转变温度的变化有关，这是由于这些区域的成分变化而发生的。热影响区域中的马氏体相分数可能对这些接头的功能特性产生重大影响。 (C) 2016 Elsevier Inc. 保留所有权利。
Although laser welding is probably the most used joining technique for NiTi shape memory alloys there is still a lack of understanding about the effects of laser welding parameters on the microstructural induced changes: in both the heat affected and fusion zones martensite may be present, while the base material is fully austenitic. Synchrotron X-ray diffraction was used for fine probing laser welded NiTi joints. Through Rietveld refinement the martensite and austenite phase fractions were determined and it was observed that the martensite content increases towards the weld centreline. This is related to a change of the local transformation temperatures on these regions, which occurs due to compositional variation in those regions. The martensite phase fraction in the thermally affected regions may have significant implications on functional properties on these joints. (C) 2016 Elsevier Inc. All rights reserved.