MECHANICAL BEHAVIOR OF Al-20Mg ALLOY SOLIDIFIED UNDER HIGH PRESSURE

Abstract

Pressure is, like temperature, a basic thermodynamic variable which can be used to alter the matter state. The atom volume, free energy of matter and other physical and chemical properties can be changed due to the application of high pressure. Many interesting materials including superconducting, super-hard, amorphous, nanomaterials can be prepared under high pressures. Meanwhile, the application of high pressure during solidification of metallic materials has also attracted much attention of researchers in recent years. However, the understanding of high pressure on alloy solidification behavior is still lacked, and needs more experimental and theoretical investigation. In the present work, the effect of high pressure on solidification microstructure, phase constitution and mechanical properties of Al-20Mg alloy was investigated by OM, XRD and tensile test. Influence of solute distribution on mechanical properties of solid solution was analyzed and the corresponding mechanism was discussed based on the solute strengthening theory. The results showed that the amount of intermetallic compound b-Al3Mg2 decreases and the amount of Al(Mg) solid solution increases in the Al-20Mg alloy solidified under high pressure, resulting in the remarkable enhancement of the mechanical properties. The Al-20Mg alloy is fragile under 1.0×10 Pa. However, it can transform to be a ductile material with elongation of 11% when solidified under 2 and 3 GPa. *国家自然科学基金项目 51171054和51001041及博士后科学基金项目2013M530913资助 收到初稿日期2013-11-25,收到修改稿日期2014-03-15 作者简介:接金川,男, 1981年生,博士 DOI: 10.11900/0412.1961.2013.00767 第971-978页 pp.971-978