Laser Shock Peening (LSP) to Improve the Metallurgical and Mechanical Properties of Gas Tungsten Arc Welding (GTAW) Joints in Hastelloy C-276
S.A. Nithin Joseph Reddy, S. Prabhakaran, S. Kalainathan, N. Arivazhagan and M. Manikandan
The present study investigates the effect of laser shock peening (LSP) to enhance the metallurgical and mechanical properties of weld joints in Hastelloy C-276. The joint was fabricated by the gas tungsten arc welding (GTAW) with ERNiCrMo-3 filler wire. LSP was carried out on the top surface of the fusion zone. An optical microscope and a scanning electron microscope (SEM) were used to compare the as-welded and laser shock peened microstructure on the fusion zone. The results show that the refined microstructure was observed in the laser shock peened fusion zone compared with the as-welded microstructure. The X-ray diffraction (XRD) result shows a 50% reduction in grain size after LSP. The effect of microsegregation also reduced in the laser shock peened zone. The laser shock peened zone shows slightly higher surface roughness, and improved hardness and strength compared to as-welded zone.
Keyword: Nd:YAG laser, Hastelloy C-276, ERNiCrMo-3 filler wire, gas tungsten arc welding (GTAW), laser shock peening (LSP), microstructure, mechanical properties, segregation