Effects of Be on impact strength of Al-Si alloys containing Fe

Abstract

Effects of solution treatment and addition of a small amount of Be on the impact strength and structure of Al-Si alloys containing Fe were examined by means of impact tests.The results obtained were summarized as follows.(1) The impact strength of Al-11% Si alloys was linearly decreased with increasing Fe content in the range beyond 0.13% Fe. After solution treatment at 500°C, the strength was markedly improved when Fe content was smaller, and the effect diappeared at about 1.5% of the content.(2) The impact strength of Al-11% Si alloys tended to be decreased with the addition of Be, both for as cast and heat treated (at 500%C) alloys.After Al-13% Si alloys containing Fe, to which Be had been added, was heat treated, the strength was markedly varied according to Fe content. It was kept nearly constant up to 1.02 or 1.32% of Fe by the addition of 0.2 or 0.5% Be, respectively.(3) Acicular crystallites were observed in Al-Si alloys, which had lower impact strength with decreasing Fe content. However, the shape of crystallites was converted into roundish patterns of Chinese script character type.