1986 Volume 4 Issue 3 Pages 514-520
The article gives the results of studying the effect of welding atmosphere such as vacuum at 4 and 4×10-3 Pa, and Ar, H2 and air at 1×105 Pa, on composition and pressure of the residual gas in voids present in diffusion-welded joints. The residual gas analysis was carried out using a mass spectrometer system evacuated to less than 4×10-6 Pa. Measurements were made both prior to and after breaking the diffusion-welded joints inside the apparatus. The materials examined were aluminum, iron, copper, titanium, SUS304 stainless steel and Ti-6AL-4V alloy, and the results obtained are as follows:
The inert gas amount in the voids is constant for a given inert gas pressure in the welding atmosphere. For gases which react with the base metal to form compounds we do not detect their presence in voids. In the case of gases that dissolve in the base metal but do not form compounds, the gas pressure approaches a value which is in equilibrium with the gas content of the metal.