Shock wave induced nanocrystallization during the high current pulsed electron beam process and its effect on mechanical properties

摘要

In this paper, the effect of high current pulsed beam (HCPEB) treatment induced nanocrystallization via shock waves in the mechanical properties of Al-15Si alloy was studied in detail. First, many fine nanograins formed on the top surface of the HCPEB-treated hypereutectic Al-15Si alloy and showed radial arrangement around the centre of the crater during the HCPEB process as a result of the impact of the shock wave induced by crater eruption. Second, the cross-section analysis revealed that some platelike eutectic Si phases in the heat-affected zone were broken, which was attributed to the repeated impact of the shock wave under high temperature conditions. Third, many nanograins (Al) were formed in the heat-affected zone, which could be tightly related to the shock wave impact during the HCPEB process. Finally, the mechanical properties of the Al-15Si alloy before and after HCPEB treatment were measured, and the results showed that the tensile strength of the HCPEB-treated Al-15Si alloy increased approximately 41.4% from 138.8 MPa for the initial sample to 196.2 MPa for the modified sample. Therefore, HCPEB treatment is a versatile technique for refining the surface microstructure of hypereutectic Al-Si alloys. (C) 2018 Elsevier B.V. All rights reserved.