Heat treatments effect on microplasma welded joints of Ni-Cr dental alloys

A distinguishing feature of Ni-Cr alloys is that their properties are developed by heat treatments. Purpose: The aim of the study was to evaluate the effect of pre- and post-weld heat treatments on Ni-Cr dental alloys. Materials and Methods: Plates of different Ni-Cr alloys were cast conventionally. Half of them were slowly and half were rapidly cooled. The plates were microplasma welded and half of them were heat treated. They were analyzed macroscopically, metallographic, and the microhardness was determined in the base metal (BM), weld metal (WM) and heat affected zone (HAZ). Results: The dendritic microstructure of the BM became finer and the microhardness increased after heat treatments. Metallographic analyses showed fewer cracks along the joining line for the pre-weld heat treated samples. Conclusion: The composition of the Ni-Cr alloys is decisive for their behavior to heat treatments. Keywords: heat treatment, microplasma welding, Ni-Cr alloys