Laser alloying of Al with mixed Ni, Ti and SiC powders

Abstract

Laser alloying of aluminium AA1200 was performed with a 4.4kW Rofin Sinar Nd:YAG laser to improve the surface hardness. Alloying was carried out by depositing Ni, Ti and SiC powders of different weight ratios on the aluminium substrate. The aim was to form surfaces on aluminium reinforced with metal matrix composites and intermetallic phases. The laser parameters used were 4kW power and 10mm/s laser scanning speed. The microstructures formed were examined using optical and scanning electron microscopes and the phases were identified with XRD and EDX analytical techniques. Preliminary results showed that the microstructure of the alloyed layer depends on the content of Ni, Ti and SiC in the deposited powder mixture. The distribution of the SiC particles was not homogeneous. Intermetallic phases were formed between Al-Ni-Ti-SiC during laser alloying. An increase in surface hardness was achieved after laser alloying. A surface hardness of approximately 356.8±43.4 HV0.1 was achieved after alloying with a powder containing 70wt%Ni, 20wt%Ti and 10wt%SiC. The increase in hardness was attributed to the formation of the intermetallic phases.