Structure and properties changes of Al-Si alloy treated by pulsed electron beam

Using up-to-date methods of material studies, it is revealed that the structure of as cast Al-Si alloy (silumin) is multi-phased and morphologically heterogeneous. It consists of solid solution grains and eutectic Al-Si with a diverse morphology. With the help of selective etching intermetallic compounds (AlNiCu and AlMg) are detected on the grain boundaries of α-solid solution. Treatment of silumin samples by the intense pulsed electron beam with the diverse density results in release of the second phase sub-micro and nano-dimensional particles. According to experiments optimal energy densities of the electron beam are 25, 30 and 35 J/sm². Silumin irradiation results in a manyfold advance of mechanical and tribological properties of the surface layers. As found out, these characteristics of the surface layers change significantly due to the sub-micro and nano-dimensional structure of cellular crystallization formed by the electron beam, which is free of primary inclusions consisting of silicon and intermetallic compounds.