Laser surface remelting of a Cu-Al-Ni-Mn shape memory alloy
Laser surface remelting of a Cu-Al-Ni-Mn shape memory alloy
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DOI：
10.1016/j.msea.2016.03.021
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发表时间：
2016-04-20
期刊：
影响因子：
6.4
通讯作者：
Bolfarini, Claudemiro
中科院分区：
文献类型：
--
作者：
da Silva, Murillo Romero;Gargarella, Piter;Bolfarini, Claudemiro
铜基形状记忆合金（SMA）比传统的钛基SMA具有更好的导热性和导电性、更低的成本和更容易加工，但它们表现出较低的延展性和较低的疲劳寿命。这些性能可以通过减小晶粒尺寸和减少显微组织偏析来改善，这可以使用激光表面重熔处理来获得。本工作的目的是生产和表征激光重熔Cu-11.85Al-3.2Ni-3 Mn形状记忆合金板。在第一步骤中通过吸铸生产尺寸为50 X 10 X 1.5mm的十二个板。之后，用300 W的激光束功率、50%的阴影并使用三种不同的扫描速度：100、300和500 mm/s再熔化板的表面。通过光学显微镜、扫描电子显微镜、X射线衍射、差示扫描量热法以及拉伸和显微硬度测试对板材进行了表征。重熔区呈T形，扫描速度分别为100、300和500 mm/s时重熔板的平均厚度分别为52、29和23 gm。在以100和300 mm/s重熔的板中，由于锁孔不稳定性，在轨迹中心周围发现一些孔隙。在激光重熔涂层中获得了与铸态样品中形成的相同的相：具有锯齿形形貌的单斜β '（1）马氏体相。然而，激光处理的样品表现出较低的转变温度比铸态样品，由于在表面处的晶粒细化。与铸态样品相比，它们还显示出机械性能的改善，断裂应力增加高达162 MPa，延展性增加高达2.2%，显微硬度增加高达20.9 HV，这使得激光表面重熔成为改善Cu基SMA机械性能的有前途的方法。(C)2016爱思唯尔B. V.保留所有权利。
Cu-based shape memory alloys (SMAs) show better thermal and electrical conductivity, lower cost and are easier to process than traditional Ti-based SMAs, but they exhibit a lower ductility and lower fatigue life. These properties can be improved by decreasing the grain size and reducing microstructural segregations, which may be obtained using laser surface remelting treatments. The aim of the present work was to produce and characterize laser remelted Cu-11.85Al-3.2Ni-3Mn SMA plates. Twelve plates with the dimensions of 50 x 10 x 1.5 mm were produced by suction casting in a first step. The surface of the plates was remelted afterwards with a laser beam power of 300 W, hatching of 50% and using three different scanning speeds: 100, 300 and 500 mm/s. The plates were characterized by optical and scanning electron microscopy, X-ray diffraction, differential scanning calorimetry as well as by tensile and microhardness tests. The remelted region showed a T morphology, with average thickness of 52, 29 and 23 gm for the plates remelted with scanning speeds of 100, 300 and 500 mm/s, respectively. In the plates remelted with 100 and 300 mm/s, some pores were found around the center of the track, due to the keyhole instability. The same phase formed in the as-cast sample was obtained in the laser remelted coatings: the monoclinic beta'(1) martensitic phase with zig-zag morphology. However, the laser treated samples exhibit lower transformation temperatures than the as-cast sample, due to grain refinement at the surface. They also show an improvement in the mechanical properties, with an increase of up to 162 MPa in fracture stress, up to 2.2% in ductility and up to 20.9 HV in microhardness when compared with the as-cast sample, which makes the laser surface remelting a promising method for improving the mechanical properties of Cu-based SMAs. (C) 2016 Elsevier B.V. All rights reserved.