Effects of laser peening on maraging steel

• Main Author: Wong, Kenneth Zhi Hao
• Other Authors: Zhou Wei
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Manufacturing; Engineering::Materials; Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/141235
• Institution: Nanyang Technological University

Laser Shock Peening (LSP) has the ability to change the mechanical properties of the material. For the purpose of this study, the material in discussion would be additively manufactured maraging steel. Maraging steel is classified as ultra-high strength steel and is most often used in the airforce to manufacture aircraft blades to withstand damage from debris. With technological advancements in additive manufacturing of maraging steel, it has opened the doors for many industries to create strong near net shaped parts to suit their specific needs. Combining this with laser shock peening, it could further improve the properties of additively manufactured maraging steel. For the purpose of this experiment, three samples of maraging steel were prepared. Two samples were laser shock peened, of which one was with an ablative layer and one without. The last sample was kept as-is. The samples undergone similar sample preparation and was examined through a series of tests designed to obtain results from several parameters such as surface profile, residual stress, hardness and microstructure. The results of the tests have shown that laser shock peening improved the surface profile of maraging steel. The hardness of maraging steel was also improved but only up till a certain depth. It was also noted that laser shock peening without an ablative layer will harden the maraging steel while at the same time inducing detrimental tensile residual stress. The difference in internal microstructure of the three samples were not distinct, which suggests that future study is required with more advanced microscopy techniques.