Laser - Induced Surface Modification in A319AI Alloy

摘要

In this work, attempt has been made to laser surface coat A319Al alloy with iron oxide (FeO and Fe_3O_4). Also, A319Al was remelted with laser on the surface for comparison of microstructural changes and corresponding mechanical properties with iron oxide composite coatings. Iron oxide, due to its reaction-induced bond, is expected to form adherent interface with the matrix. Microstructures indicate extreme refinement in both laser surface melted region and laser-coated region. Nanoindentation was carried out to evaluate the property of local volumes in an attempt to correlate with wear performance. Average hardness of the laser treated samples showed an increase over that of the as-received A319Al. However, there were only marginal changes in corresponding elastic modulus. The expected change was in the scattering (given by standard deviation) of the hardness in the laser treated samples, which was significantly less compared to that in the as-received substrate material. Scratch test was carried out at different applied normal load to find out the load sensitivity of wear resistance of the coating. The laser-modified samples were relatively insensitive to normal load, whereas the as-received A319Al was found to have lower scratch hardness at higher load. Fe_3O_4-coating has consistent scratch hardness making it superior to all other samples.