[Basic study on laser welding of Ag-Pd-Cu-Au alloy. Part 2. Mechanical properties and heat treatment].

Laser welded material must have enough mechanical strength withstanding the biting impact and stress. In case of Ag-Pd-Cu-Au alloy, the mechanical properties proved to be changed by heat treatment. The heat treatment before and after welding influences the mechanical properties of welded material. The purpose of this study was to evaluate the influence of heat treatment for the mechanical properties of laser welded material.Specimens, rolled sheets of 1.2mm thickness, were welded by a pulsed Nd: YAG laser, Test pieces were made of specimens with different heat treatment before and after welding, then tensile test and Vickers hardness test were performed.The hardness of the weld by laser irradiation was higher than that of solution treated base metal. The tensile strength of the laser welded specimen was nearly equal to the solution treated base metal. And the welded specimen after ageing had nearly equal to or higher tensile strength than the soldered specimen. In the fractured surface of laser welding specimen by tensile test, the dimple showing the ductile fracture was observed.