Parametric investigations in pulsed laser-assisted hatch patterning and nitriding of A356 cast aluminum alloy in liquid nitrogen environment for improving mechanical and tribological properties

Abstract

In the present study, a novel technique to replace conventional honing with a laser hatch patterning accompanied by nitriding called pulsed laser hatch patterning and nitriding (PLHN) process has been identified and reported in detail. Effect of process parameters like laser wavelength (532 and 1064 nm) and N2 gas flow rate (5–35 L/min) on the nitride layer quality, average roughness, hardness, and elevated temperature tribological performance of A356 cast Al alloy has been investigated. The formation of a thin AlN layer was confirmed from (GIXRD and XPS) analysis. The crack-free nitride layer was produced with a maximum thickness of 13.48 ± 0.53 µm, and 11.35 ± 0.34 µm using laser wavelengths 532 nm (at 15 L/min) and 1064 nm (at 25 L/min), respectively. At these optimized process parameters, the PLHN specimen processed at 532 and 1064 nm laser wavelengths showed a maximum of 212.57 and 144.73% increment hardness values as compared to the base material (1.52 Gpa). While the wear rate (200 °C) was reduced by 43.25% and 36.48% for the PLHN specimen processed at 532 nm and 1064 nm, respectively in comparison with the base material.