Joint efficiency of laser-welded silver–palladium and cobalt–chromium alloys

Abstract

Purpose Laser welding is an important recent method to join prosthetic metal frameworks. However, no previous study investigated the effect of laser parameters on silver–palladium alloys. Therefore, the purpose of this study was to investigate the effect of laser voltage on the welding efficiency of laser-welded silver and cobalt–chromium alloys. Materials and methods Cast plates of silver (Ag) and cobalt–chromium (Co) alloys were prepared (0.5×3.0×10 mm) and polished (600 grit, SiC paper). After they were butted against each other (Ag/Co), laser-welded specimens were prepared using Nd:YAG laser at a pulse duration of 10 ms, spot diameter of 1 mm, and voltages of 200, 220, 240, and 260 V. The weld pattern comprised five laser spots bilaterally. Nonwelded cast specimens were also prepared of both alloys and served as controls. Fracture load and percent elongation were measured using a universal testing machine at a crosshead speed of 1.0 mm/min. The data ( n = 5) were statistically analyzed using the analysis of variance/Tukey's HSD post-hoc test (α = 0.05). Results Increase in laser voltage led to increased fracture load and percent elongation. There was no statistically significant difference in fracture load value between Ag control (993 N) and Ag/Co welded at 260 V (950 N). Moreover, there was no statistically significant difference in percent elongation between Co control (2.3%) and Ag/Co welded at 260 V (2%). Conclusion Under laser parameters used in this study, the highest obtained fracture load of laser-welded Ag/Co at 260 V was statistically equivalent to nonwelded Ag. Moreover, the highest obtained percent elongation of laser-welded Ag/Co at 260 V was statistically equivalent to that of nonwelded Co.