# A Comprehensive Review on the Enhancement Mechanism of Fatigue Performance in Titanium Alloys via Laser Shock Peening

## TL;DR

This paper reviews how laser shock peening improves the fatigue performance of titanium alloys by altering their microstructure and residual stresses.

## Contribution

The paper systematically discusses the enhancement mechanisms of fatigue performance in titanium alloys via laser shock peening, including microstructure evolution and residual stress redistribution.

## Key findings

- Laser shock peening induces compressive residual stresses that suppress crack initiation and propagation.
- Nanostructures like nanotwins and dislocations enhance mechanical hardness and fatigue resistance.
- LSP reduces porosity and alters crack initiation sites, increasing crack propagation threshold.

## Abstract

This paper reviews the enhancement mechanisms of fatigue performance in titanium alloys processed by laser shock peening (LSP). Because of the redistribution of residual stress and micro-crack and pore behavior, micro–nanostructure evolution and surface roughness effect are systematically discussed. LSP induces beneficial compressive residual stresses at the surface, effectively suppressing crack initiation and propagation. Notably, the nanostructures induced by this process—including nanotwins, dislocations, stacking faults, and nanocrystals—collectively enhance the material’s mechanical hardness, strength, and fatigue resistance. Furthermore, LSP reduces porosity, alters pore morphology and alters crack initiation sites, thereby increasing the crack propagation threshold. However, the influence of LSP on material toughness remains a subject of debate. The insights provided herein offer valuable theoretical guidance for the development of high-performance titanium alloys and further optimization of LSP technology.