Carbide Addition on Aluminum Alloy Surface by Plasma Transferred Arc Welding Process(Surface Processing)

Effect of carbide addition on the surface characteristics of aluminum alloy 5083 has been investigated with the plasma transferred arc welding process (DCSP) of NbC, TiC or SiC powder. Optimum overlaying conditions under which bead appearance is superior and porosities in overlaid metal are lesser are determined. Moreover some characteristics of overlaid metal containing carbide are evaluated under these optimum conditions. The results are summarized as follows: (1) The maximum area fraction of carbide in overlaid metal is about 40% for NbC and TiC, and about 30% for SiC, (2) Vickers hardness of overlaid metal containing carbide is in the range between 111 and 141hgf/mm2, (3) Abrasive resistance of overlaid metal at higher sliding speed is remarkably improved by the addition of carbide although that at lower sliding speed is not almost improved, (4) In the 180 degree bend test, cracks appear not in the boundary layer between overlaid and base metals but only in overlaid zone, meaning that the boundary layer is sound enough for ductility.