A review of the effects of laser shock peening on properties of additively manufactured Ti6Al4V

By creating compressive residual stresses on Ti6Al4V (Ti64) structures, laser shock peening (LSP) improves fatigue performance. The effect of the main LSP parameters on residual stress, microstructure, and fatigue life of laser additively manufactured Ti6Al4V is discussed in this chapter. Due to an excessively unfavorable residual stress profile, laser additively manufactured Ti6Al4V parts often exhibit poor fatigue performance. LSP involves the application of short pulses of energy from a high-power laser to the material surface, which results in residual compressive stress, grain refinement, and improved mechanical performance. In contrast to machining, which may expose internal defects due to near-surface pores being cut open by material removal during the surface finishing process, LSP does not expose underlying pores and may improve surface condition and even partly or fully close undersurface pores, making it a preferable postprocess method. However, in order to reap the benefits of LSP effectively, it is best to select laser peening conditions that can produce the desired microstructure as well as the required level of compressive residual stresses near the surface without causing significant negative influences in surface roughness. The purpose of this paper is to provide documentation of a review of the effectiveness of LSP in the fatigue enhancement of Ti64 parts manufactured using laser additive manufacturing.