Laser peening, also known as laser shock peening (LSP), is an advanced surface engineering process that uses high-energy pulsed laser beams to generate deep compressive residual stress in metal components. Unlike traditional surface treatments, laser peening creates compressive stress layers that extend 1-2mm beneath the surface—with maximum depths reaching up to 12mm in optimized applications [4]. This depth is 5-10 times greater than conventional shot peening, making it particularly valuable for critical components subjected to extreme fatigue loading.
The process works by directing short-duration, high-energy laser pulses (typically 8-16 nanoseconds pulse width, up to 10 joules energy) onto the component surface. When the laser pulse strikes the surface, it creates a plasma expansion that generates a high-pressure shockwave. This shockwave propagates into the material, inducing plastic deformation and creating beneficial compressive residual stress [5]. The compressive stress layer acts as a protective barrier against fatigue crack initiation and propagation, significantly extending component service life.
The plasma expansion generates a pressure wave that induces residual compressive stress similar to peening media impact, but with much greater depth and precision [5].
Laser peening technology was first discovered in the 1960s but only became commercially viable in the 1990s with advances in high-energy laser systems [6]. Today, three main system types are available: high-energy low-repetition-rate systems for deep treatment, medium-energy medium-repetition-rate systems for balanced performance, and low-energy high-repetition-rate systems for high-throughput applications. Each system type serves different industrial requirements, from aerospace critical components to automotive mass production.
