Hot tearing is the formation of a fracture in a metal casting during solidification as a result of hindered contraction. In this study we tried to evaluate the hot tearing susceptibility of different silver alloys with 925‰ fineness. Several studies on hot tearing susceptibility of casting alloys are known, but we have not been able to find information on precious alloys. Therefore, we wanted to characterize 925‰ silver alloys that, according to our experience, are more prone to this kind of problem. A classic 925‰ silver alloy was taken into consideration, and we evaluated the effects of additions of other elements. We compared the different behavior of binary, ternary and quaternary alloys, with and without small additions of elements such as deoxidizers or grain refiners. In addition, we carried out a metallurgical analysis on cracked areas, trying to correlate the behavior of the alloys with their microstructure. This paper is a part of a wider research aimed at developing silver alloys with high resistance to tarnish and a reduced tendency to hot tearing.

Author: Daniele Maggian, Silvano Bortolamei, Alessandro Zocca, Mauro Di Siro, David Frizzo, David