Microstructure and mechanical properties of 7005 aluminum alloy processed by one-pass equal channel reciprocating extrusion
(1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;
2. School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China)
2. School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: An equal channel reciprocating extrusion (ECRE) was proposed first to obtain a severe plastic deformation (SPD) of 7005 alloy. The microstructure and mechanical properties of one-pass ECREed (ECRE processed) 7005 alloy were investigated. The results show that SPD occurring in ECRE leads to a mixed microstructure. ECREed 7005 alloy exhibits a significant improvement of ultimate tensile strength (UTS) and elongation. Mechanical properties in the region undergoing a complete ECRE process are higher than those in the region undergoing an incomplete ECRE process due to larger dislocation strengthening effect. Yield strength (YS) and UTS first decrease and then increase with an increase of extrusion temperature. The YS of 359.2 MPa, UTS of 490 MPa and elongation of 17.7% are obtained after T6 treatment. Fine-grain strengthening, dislocation strengthening and precipitation strengthening in the T6-treated ECREed sample all play important roles in improving the mechanical properties.
Key words: 7005 aluminum alloy; equal channel reciprocating extrusion; microstructure; mechanical properties