Three body abrasion of laser surface alloyed aluminium AA1200

Laser surface alloying of aluminium AA1200 was performed with a 4 kW Nd:YAG laser to improve the abrasion wear resistance. Aluminium surfaces reinforced with metal matrix composites and intermetallic phases were achieved. The phases present depended on the composition of the alloying powder mixture. The wear performance of the alloyed surfaces was characterised using an ASTM G65 three body dry abrasion apparatus. A maximum 82% improvement in the wear resistance of the pure aluminium was achieved with a 40 wt% Ni+20 wt% Ti+40 wt% SiC composition. The three alloys which had the best wear resistance were all produced with a composition of 40 wt% SiC and Ti and Ni powders ranging from 20 to 40 wt%. No direct correlation was observed between hardness and wear resistance. Microstructural examination showed that the main wear mechanisms were intense plastic deformation with micro-fracture of the SiC particles and intermetallic phases. The wear behaviour is mainly determined by the response of the different alloy phases, either independently or in combination, to the action of the abrasive particles and the precise nature of this response is complex and requires further study.

► Novel laser surface alloying of Al AA1200 with mixed Ni, Ti, SiC proportions. ► Maximum 82% reduction in abrasion wear rate achieved. ► Improvement in abrasive wear dependent on alloying composition.