Heat treatments result in Mg loss by diffusion from AlMgSi alloys. This was identified by many authors using different bulk measurements. Up to the present indirect methods have been applied to check the evaporation of Mg. We studied this problem by soft X-ray emission spectroscopy (SXES) in the region of the L2,3 emission peak of Al (approx. 17 nm) in a 150 nm thick layer. The heat treatment was made by electron beam, using the same beam also for the X-ray excitation, so the change of the Mg concentration in the surface layer was measured in vacuum undisturbedly. Our results show that the Mg concentration essentially increases during the heat treatment near the surface. The bulk concentration of the Mg was 0,6 wt% and we recorded the same concentration in the initial state of the alloy on the surface too. After the heat treatment the concentration achieved a value of 70 wt% near the surface. The heat treatment was made at 480±30 K.
ASJC Scopus subject areas
- Nuclear and High Energy Physics