Riei Ichikawa

Change of distribution of beryllium in the alloys of magnesium with beryllium when heated

The distribution of beryllium in the surface parts of solid magnesium alloys containing beryllium after heated at 300°, 400°or 500°C was studied by chemical analysis, and even further, change in the weight of the samples after heating magnesium and its alloys containing 1% of Al, Ca, La, Th and Zn besides beryllium, and still further the comparison between the distribution of beryllium in the samples after heating and that of beryllium of cast samples.Results obtained are as follows:(1) The weight of pure magnesium when heated at 400°C increases far more than that of magnesium containing beryllium. Slower oxidation was observed in magnesium alloys containing 1% of Al, Ca, La, Th and Zn, besides beryllium than in pure magnesium.(2) The enrichment of beryllium is found in the superficial layer of Mg-0.005% Be after heating. This enrichment of beryllium in the surface can serve the purpose of preventing the alloys from oxidation.(3) The enrichment of beryllium in the surface varies with elements added, that is, highly enrichment is found in Mg-Be alloys containing Al and Ca, lower in the alloy containing Zn, and scarcely any in those with Th and La. The same tendency of the diffusion of beryllium to the surface is found on castings.(4) As the result of the study on the effect of the heating atmosphere on the mode of distribution of beryllium when heated, at the diffusion of beryllium to the surface is remarkable when heated in air. at 500°C, but only a little in vacuum and in argon. So this suggests that such diffusion of beryllium to the surface of the magnesium alloys is due to the strong affinity between beryllium and oxygen in air when heated.