摘要
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.
首次提出等通道往复挤压技术,用于7005铝合金以获得大塑性变形。研究单道次等通道往复挤压变形7005铝合金的显微组织和力学性能。结果表明,在等通道往复挤压中发生的大塑性变形导致变形材料由混晶组织组成。等通道往复挤压变形的7005铝合金呈现抗拉强度和伸长率的大幅提升。在经历完整的等通道往复挤压过程的区域,材料的力学性能比其他区域的力学性能高,这主要由于材料可获得更大的位错强化。屈服强度和抗拉强度随着挤压温度的升高呈现先增加后降低的趋势。当等通道往复挤压的7005铝合金经过T6热处理后,其屈服强度为359.2 MPa,抗拉强度为490 MPa,伸长率为17.7%。细晶强化、位错强化和析出相强化共同在提升热处理后材料力学性能方面起着重要作用。
基金
This work is supported by the National Natural Science Foundation of China(51875124).
