Thermal degradation of joined thick Au and Al elements Available to Purchase

Investigations were aimed at the evaluation of degradation mechanisms in ultrasonically welded joints of AlSi1 per cent wire (25 μm in diameter) and Au substrate (100 μm thick), relatively thick elements, exposed to high temperature of 300°C up to 100 h. Thermally activated Al diffusion into Au generates the formation of intermetallic compounds in the area of the bond interface. With the longer thermal exposure the expansion and transformation of intermetallic compounds is observed. The characteristic “intermetallic compounds core” is formed, which from one side penetrates into the wire material and from another spreads deeply into the Au substrate up to enhancing band of Kirkendall voids.