Dissimilar laser welding of superelastic NiTi and CuAlMn shape memory alloys
Dissimilar laser welding of superelastic NiTi and CuAlMn shape memory alloys
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DOI：
10.1016/j.matdes.2017.05.011
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发表时间：
2017-08-15
影响因子：
8.4
通讯作者：
Zhou, N.
中科院分区：
文献类型：
--
作者：
Oliveira, J. P.;Zeng, Z.;Zhou, N.
先进工程合金的异种连接是开发新应用的基础。然而，由于可能会出现几个冶金和热物理问题，连接两种不同的材料会带来困难。本文介绍了NiTi和CuAlMn形状记忆合金的室温超弹性异种激光焊接工作。对其微观结构进行了详细的表征。根据激光焊接的特点，即材料和热流、高冷却速度和熔合区内的温度梯度，解释了异种接头的复杂组织。循环拉伸试验表明，尽管熔合区的微观结构不佳，但接头仍保持了超弹性行为，当以5%的应变循环时，熔合区转变为2%的不可恢复应变。这些结果可能为基于这种不同组合的新应用打开可能性，这种组合可以结合超弹性和更高的热导率和电导率(后两个特性出现在CuAlMn形状记忆合金中)。
Dissimilar joining of advanced engineering alloys is fundamental for the development of new applications. However, joining two distinct materials poses difficulties owing to the several metallurgical and thermo-physical problems that can arise. This paper describes the work performed on dissimilar laser welding of NiTi and CuAlMn shape memory alloys, superelastic at room temperature. Detailed microstructural characterization was performed. The complex microstructure of the dissimilar joint is explained based on the characteristics of laser welding, namely material and heat flow, high cooling rates and thermal gradients within the fusion zone. Cycling tensile testing revealed that the joints preserved the superelastic behaviour despite the unfavourable microstructure of the fusion zone which translates into an irrecoverable strain of 2% when cycled at 5% strain. These results may open the possibilities for new applications based on this dissimilar combination which can combine superelasticity and higher thermal and electrical conductivity (with the latter two characteristics arising for the CuAlMn shape memory alloy).