Effects of heat treatments on mechanical strength of laser-welded equi-atomic AuCu-6at%Ga alloy.

Abstract

There is little information available on the mechanical strengthening of laser-welded gold alloys to achieve reliable dental prostheses. This study examined the hypothesis that heat treatments increase the mechanical strength of a laser-welded equi-atomic AuCu-6at%Ga alloy with age "hardenability" at intra-oral temperature. Cut cast gold alloy plates were laser-welded. The specimens were given one of three heat treatments: (1) solution treatment, (2) high-temperature aging after solution treatment, and (3) simulated intra-oral aging after solution treatment. As-cast and uncut specimens were also prepared. Tensile testing was conducted, and the breaking stress and yield strength were recorded. The yield strength values of all the heat-treated specimens nearly reached the values of the corresponding heat-treated control specimens. The results of this study indicated that, for high mechanical strength to be achieved, the laser-welded alloy tested should be aged at a high temperature or be intraorally aged after being laser-welded.