First-principles Study on the Effect of Stress on the Mechanical and Electronic Structure of 6005A Aluminum Alloy

Author of the article:FAN Letian

Author's Workplace：Product R & D Center of CRRC Tangshan Locomotive & Rolling Stock Co., Ltd., Tangshan 063000, China

Key Words： 6005A aluminum alloy; precipitated phase; first principles; mechanical properties; electronic structures; stress

Abstract：Nanoprecipitates in 6005A aluminum alloy can effectively improve the mechanical properties of the alloy. However, the size and orientation changes at the nanoscale have greatly hindered the understanding of the potential relationships between precipitates and the crystal structure. The structural stability, mechanical properties and electronic structures of Mg 5 Si 6 , Mg 9 Si 5 and Mg 2 Si precipitates in 6005A aluminum alloy with or without stress were studied by first-principles calculations. The calculated results are in good agreement with the previous experimental and theoretical results. The compressive stress can increase the toughness of the three precipitated phases and decrease the band gap of Mg 2 Si. Under stress conditions, the formation enthalpy and cohesive energy of the precipitated phase are generally increased to reduce its stability and promote the transition from a metastable to steady precipitated phase. These findings will help to further understand the structural behavior and mechanical properties of the precipitated phase of 6005A aluminum alloy and have theoretical guiding significance for improving the properties of 6005A aluminum alloy.