Influence of laser shock peening on microstructure and high-temperature oxidation resistance of Ti45Al8Nb alloy fabricated via laser melting deposition
Lulu Jiang, Liang Lan, Chengyan Bai, Ruyi Xin, Shuang Gao, Haoyu Wang, Bo He, Chaoyue Chen, Guoxin Lu
Abstract
Laser shock peening (LSP) was used to enhance the high-temperature oxidation resistance of laser melting deposited Ti45Al8Nb alloy. The microstructure and high-temperature oxidation behavior of the as-deposited Ti45Al8Nb alloy before and after LSP were investigated by scanning electron microscopy, X-ray diffraction, and electron backscatter diffraction. The results indicated that the rate of mass gain in the as-deposited sample after LSP exhibited a decrease when exposed to an oxidation temperature of 900 °C, implying that LSP-treated samples exhibited superior oxidation resistance at high temperatures. A gradient structure with a fine-grain layer, a deformed-grain layer, and a coarse-grain layer was formed in the LSP-treated sample, which facilitated the diffusion of the Al atom during oxidation, leading to the formation of a dense Al 2 O 3 layer on the surface. The mechanism of improvement in the oxidation resistance of the as-deposited Ti45Al8Nb alloy via LSP was discussed.