The influence of beryllium addition on the microstructure and mechanical properties of Al–15%Mg2Si in-situ metal matrix composite

The effects of Beryllium (Be) on the microstructure and mechanical properties of Al–15%Mg2Si composite were investigated. The results showed that with the increase of Be content, the average size and volume fraction of primary Mg2Si particles decreases. Pseudo-eutectic Mg2Si has mainly a fine fibrous structure in both specimens with and without Be. However, in the samples containing Be, the path for crack propagation along cell boundaries is very tortuous. Meanwhile, βAl–Mg–Be phase based on a β-Al3Mg2 phase of the Al–Mg system was observed in specimens containing Be. It was found that with the addition of Be the ultimate tensile strength (UTS) and elongation values improved. A study of the specimenʹs fracture surfaces via scanning electron microscope revealed that Be increases the number of fine dimples and decohered Mg2Si particles.