Effect of laser shock peening on microstructure and fatigue property of TA15 titanium alloy with double holes

doi:10.13251/j.issn.0254-6051.2023.07.042

Abstract

Abstract: TA15 titanium alloy were treated by laser shock peening (LSP) to study the effect of LSP on microstructure and fatigue property of the titanium alloy specimens with double holes. The results show that when the specimens are treated by LSP with laser energy of 25 J, circular spot diameter of ?4 mm and shock times of 2, a large number of high-density dislocations and dislocation walls are formed in the TA15 titanium alloy crystal, and introducing residual compressive stress of up to -500 MPa simultaneously on the material surface which can balance the tensile stress generated under fatigue load, effectively suppress fatigue crack initiation and slow down crack propagation rate. The LSP can obviously improve the fatigue life of the titanium alloy specimens with double holes, which is increased by 60%-89% compared to that of the untreated specimen. This is because the large residual compressive stress introduced by LSP greatly reduces the effective stress intensity factor at the crack tip. When the effective force intensity factor is less than the fracture toughness of the material, the fatigue crack growth will be suppressed or stopped, thus improving the fatigue life.

Key words: laser shock peening, TA15 titanium alloy with double holes, microstructure, residual compressive stress, fatigue property

CLC Number:

TG178

Han Peipei, Zang Xu, Dong Zhi, Li Shijian, Jiao Qingyang, Deng Xiguang. Effect of laser shock peening on microstructure and fatigue property of TA15 titanium alloy with double holes[J]. Heat Treatment of Metals, 2023, 48(7): 254-258.

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