TiNi记忆合金电子束熔覆层的组织性能研究

Microstructure and Properties of Electron Beam Cladding Layer of TiNi Shape Memory Alloy

目的利用电子束熔覆技术将TiNi记忆合金熔覆在TC4的表面,开展熔覆层耐磨性能研究,以此来改变材料的表面性能,达到实际应用的要求。方法通过SEM、EDS、维氏显微硬度计和摩擦磨损试验机,对熔覆层的宏观形貌、显微组织、元素分布、显微硬度以及摩擦磨损性能等进行测试分析。结果制备出的熔覆层表面成形良好、无气孔、无裂纹,并且与基体实现了良好的冶金结合。熔覆层由表及里的硬度升高,其值最高可达HV625,较TC4母材(HV350)的硬度有明显的提高。通过磨损试验曲线表明,TiNi合金熔覆层和TC4基材稳定后的平均摩擦因数为0.052和0.169,比磨损率为0.96×10^(-4)和2.28×10^(-4) mm^3/(N·m)。结论TiNi熔覆层的耐磨性能较TC4基材的耐磨性能显著增强,可以达到减磨的效果。

The paper aims to clad NiTi memory alloy onto the surface of TC4 with electron beam cladding technologyto study wear resistance of the cladding layer to change the surface properties of the material and meet the requirements on actual application.SEM,EDS,Vickers microhardness tester and friction and wear tester were used to test the macroscopic morphology,microstructure,element distribution,microhardness and friction and wear property of the cladding layer.The surface of the cladding layer was well-formed without pore,no crack,and it achieved a good metallurgical bond with the substrate.The hardness of the cladding layer increased from the surface to the inside,and its value was up to HV625,which was significantly higher than that of the TC4 base metal(HV350).The test curve chart showed that the average friction coefficient of the TiNi alloy solder layer and TC4 substrate after stabilization was 0.052 and 0.169,and the wear rate was 0.96×10^-4 mm3/(N·m)and 2.28×10^-4 mm^3/(N·m).The wear resistance of TiNi alloy cladding layer is significantly higher than that of the TC4 substrate,and the wear reduction effect can be achieved.