Mechanical characterisation of laser surface alloyed aluminium–copper systems

Additional elements (copper and aluminium) were pre-placed on the aluminium surface and laser alloyed. This pre-placed layer technique gave excellent results concerning micro-hardness, microstructure homogeneity and porosity elimination. The obtained Al–Cu alloys were homogeneous and the micro-hardness varied from 60 to 250 HV0.2 for 6–40 wt.% Cu. Nano-indentation measurements showed an increase in elastic modulus and particularly in plasticity index. All of these measurements predicted an improved wear behaviour of these coatings compared with pure aluminium. A pin-on-disk-type device confirmed the improvement of mechanical properties. In this case, the mass loss can decrease by a factor of 15 between a virginal specimen and a 40 wt.% Cu alloy. In addition, a transition of damage mechanism from a severe wear to a mild wear was observed as the copper ratio of the alloy increased. Wear tracks became homogeneous and wear rate was decreased.