激光冲击强化对激光增材TC4钛合金组织和抗氧化性的影响

近年来,激光增材制造技术(3D打印)成为科学研究及工业应用领域的热点。为了研究激光冲击强化对增材制造TC4钛合金性能的影响,本文采用能量为5 J,波长为1 064 nm,脉宽为10 ns,光斑直径为3 mm的脉冲激光对3D打印TC4钛合金进行激光冲击强化,分析了激光冲击强化前后材料的显微硬度、显微组织、残余应力以及高温氧化性能。结果表明,经过激光冲击强化后,材料的显微硬度比激光冲击强化前提高了8%,影响层深度达到0.4 mm,强化区域的晶粒得到细化,位错增多,并产生形变孪晶;激光冲击强化的残余压应力数值高达472 MPa,材料的高温抗氧化性能也得到改善。

Influence of laser shock peening on microstructure and oxidation resistance of laser additive manufactured TC4 titanium alloy

In recent years, laser additive manufacturing(also called 3D printing) has become the focus of scientific research and industrial applications. In order to study the impact of laser shock peening(LSP) on the properties of laser additive manufactured Ti-6Al-4V alloy, a TC4 titanium alloy prepared by 3D printing was carried out LSP by using Nd:YAG laser with energy of 5 J, wavelength of 1 064 nm, pulse width of 10 ns and spot diameter of 3 mm, and the micro-hardness, microstructure, residual stress and high temperature oxidation performance of the material before and after LSP were analyzed. The results show that by comparing with the TC4 titanium alloy before LSP, the micro-hardness of that after LSP increases by 8%, and the depth of the impact layer reaches 0.4 mm, the grains in the strengthened region are refined, the dislocation is increased and the deformation twins are produced. The residual compressive stress of laser shock peening is as high as 472 MPa, and the high temperature oxidation resistance of the material is also improved.