New research perspectives open up with a research project collaboration entitled Effectiveness of Laser Shock Peening in Post-processing Additive Manufactured metal components. It has been initiated between the University of Pretoria, Department of Materials Science and Metallurgical Engineering and the University of Sousse, Department of Mechanical Engineering. The project’s theme is the Investigation of the laser shock peening effect on the pore closure of 3d printed metal samples (experimental and numerical approach).
Additive Manufacturing (AM), commonly known as 3D printing, has revolutionized the production of complex metal components across aerospace, biomedical, and automotive industries. Its ability to create intricate, lightweight, and customized geometries directly from digital models offers unparalleled design freedom.
Consequently, post-processing techniques have become an indispensable step in the AM workflow, aiming to transform the "as-built" material into a reliable engineering component. While conventional methods like heat treatment (stress relief) and Hot Isostatic Pressing (HIP) are effective in reducing porosity and homogenizing the microstructure, they often fall short in addressing the fatigue performance, which is highly sensitive to surface conditions and residual stress states.
It is within this gap that advanced surface enhancement technologies like Laser Shock Peening (LSP) have emerged as a transformative solution. Laser Shock Peening is a sophisticated cold-working process that utilizes high-intensity laser pulses to generate a controlled plasma shockwave on the surface of a component. This shockwave plastically deforms the subsurface material, inducing a deep layer of high-magnitude compressive residual stresses. In conventional manufacturing, LSP has a well-established track record for dramatically enhancing the damage tolerance and service life of critical parts like turbine blades and landing gear.
This research study examines the compelling effectiveness of applying Laser Shock Peening specifically to post-process additive manufactured metal components. The central thesis is that LSP is uniquely capable of mitigating the key limitations of AM parts. By imparting deep compressive stresses, it effectively neutralizes the detrimental tensile stresses from the build process, simultaneously work-hardening the surface and closing fine surface-breaking pores.
The synergy between LSP's ability to create a superior surface layer and AM's capacity for complex geometry presents a powerful combination. The following sections will delve into the fundamental principles of LSP, analyze its profound effects on the mechanical properties and fatigue performance of AM metals, and discuss its role in qualifying additively manufactured components for the most demanding applications.