Microstructural Characterization of a Laser Surface Remelted Cu-Based Shape Memory Alloy
Microstructural Characterization of a Laser Surface Remelted Cu-Based Shape Memory Alloy
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DOI：
10.1590/1980-5373-mr-2017-1044
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发表时间：
2018-04
影响因子：
1.7
通讯作者：
Murillo Romero da Silva;P. Gargarella;W. Wolf;T. Gustmann;C. S. Kiminami;S. Pauly;J. Eckert;C. Bolfarini
中科院分区：
文献类型：
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作者：
Murillo Romero da Silva;P. Gargarella;W. Wolf;T. Gustmann;C. S. Kiminami;S. Pauly;J. Eckert;C. Bolfarini
与传统的ti基形状记忆合金相比，cu基形状记忆合金具有相变温度高、成本低、易于加工等优点，但也存在延展性低、易晶间开裂等缺点。一些研究已经寻求一种方法来改善这些合金的机械性能，并经常使用显微组织细化。它可以通过激光重熔处理得到。研究了激光表面重熔对Cu-11.85Al-3.2Ni-3Mn (wt%) SMA显微组织的影响。使用三种不同的激光扫描速度，即100、300和500毫米/秒，对板材进行重熔。扫描速度为100、300和500 mm/s时，重熔区形貌呈t型，平均厚度为52、29和23μm，平均晶粒尺寸为30、29和23μm。在以100和300 mm/s速度重熔的钢板中，由于锁孔不稳定，在锁孔根部出现了气孔。我们发现，在较低的扫描速度下，锁孔的不稳定性变得更加明显。没有观察到激光治疗带来的任何择优取向。
Cu-based shape memory alloys (SMAs) present some advantages as higher transformation temperatures, lower costs and are easier to process than traditional Ti-based SMAs but they also show some disadvantages as low ductility and higher tendency for intergranular cracking. Several studies have sought for a way to improve the mechanical properties of these alloys and microstructural refinement has been frequently used. It can be obtained by laser remelting treatments. The aim of the present work was to investigate the influence of the laser surface remelting on the microstructure of a Cu-11.85Al-3.2Ni-3Mn (wt%) SMA. Plates were remelted using three different laser scanning speeds, i.e. 100, 300 and 500 mm/s. The remelted regions showed a T-shape morphology with a mean thickness of 52, 29 and 23 μm and an average grain size of 30, 29 and 23μm for plates remelted using scanning speed of 100, 300 and 500 mm/s, respectively. In the plates remelted with 100 and 300 mm/s some pores were found at the root of the keyhole due to the keyhole instability. We find that the instability of keyholes becomes more pronounced for lower scanning speeds. It was not observed any preferential orientation introduced by the laser treatment.