Investigation on the effect of microstructure and mechanical properties of laser cladded TC17 titanium alloy following laser shock peening

Abstract

This paper aims to determine the effects of microstructure and mechanical properties of laser cladding TC17 titanium alloy post laser shock peening (LSP) In this work, A 3J, 20ns, 1064nm wavelength, Nd:YAG laser was employed on laser cladded TC17 titanium alloy samples with multiple impacts. Micro-hardness, residual stress were measured. The microstructure of LSPned sample was mapped by Electron Backscattered Diffraction (EBSD). The residual stress results showed that a stable compressive residual stress has been formed on the cladded coating surface with a value of 190MPa due to LSP modification. Additionally, LSP also improves the surface microhardness of cladded TC17 samples with an increase rate of 13.1%. Vibration fatigue tests were designed and carried out to examine the effects of LSP on the fatigue strength of cladded TC17 specimens. Results show that the fatigue strength of unpeened cladded sample is 290MPa while of peened claded sample is 300MPa. This work will contribute to prolong the service life of repaired TC17 components in aero-engines thereby economizing the repairing costs.