Effect of laser remelting and simultaneous application of ultrasonic vibrations during laser melting on the microstructural and tribological properties of laser clad al-sic composites

Abstract

Laser composite surfacing of aluminum alloys with ceramic particles has been extensively investigated for improving tribological properties. However, the process often results in incomplete penetration of ceramic particles in the melt pool and undesirable interfacial reactions. In this paper, laser composite surfacing of 2024 aluminum alloy with SiC particles is investigated using two distinct approaches: laser remelting and laser melting under the influence of ultrasonic vibrations of preplaced powder mixture. Detailed analysis of variation of clad layer thickness, microstructure in the composite clad layer, phase/texture development, surface roughness, and sliding wear performance with laser processing conditions is presented. The analysis showed that remelting and ultrasonic vibration assist results in significant improvement in clad layer thickness and microstructure (reduction in needle-like α-Si phase). While the laser remelting resulted in significant reduction in wear rate, the specimens processed with ultrasonic vibration-assisted laser melting showed variable wear rate, likely due to complex effects of microstructural modification and enhanced surface roughness.