Microstructure and creep behaviour of laser surface alloyed aluminium

The creep behavior of a commercial purity Al surface alloyed with Ni using a pulse laser are reported. The overall creep strengthening of the laser surface alloyed Al is shown by comparing the creep behavior of the pure Al substrate with that of the bi-layer composite. The microstructure of the alloyed layer was also characterized using SEM and XRD. It was shown that the pulse laser surface alloying of the Al with approx 35 wt.% Ni resulted in a surface layer with a fine distribution of Al sub 3 Ni in primary dendritic and eutectic morphologies. The steady state creep behavior of the substrate with subgrains of 3.2 mu m followed Sherby's substructure invariant model. The laser surface alloying led to substantial creep strengthening. The creep behavior of the alloyed layer appeared to be controlled by dislocation-particle interaction.