中南大学学报（自然科学版）2017，Vol.48Issue(3)：578-584,7.DOI:10.11817/j.issn.1672-7207.2017.03.004
预时效对7020铝合金组织与性能的影响
Effects of pre-aging on microstructures and mechanical properties of 7020 aluminum alloy
摘要
Abstract
The effects of pre-ageing treatment on the mechanical properties of 7020 aluminum alloy were investigated by means of Vickers hardness (HV), electrical conductivity measurement (EC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile test and impact toughness tests. The results show that after 470℃/1 h solution treatment followed by pre-aging at 65℃, the mechanical properties of investigated alloy's increase with the increase of the pre-aging time, while impact energy increases at first and then decreases. Compared to the direct two-stage aging at 65℃/168 h+90℃/8 h+160℃/26 h, the tensile strength, yield strength and elongation are 355.9 MPa, 290.5 MPa and 16.3%, respectively; the Vickers hardness is 120.9, and conductivity is 22.4 MS/m. However, for direct two-stage aging, the tensile strength, yield strength and elongation are 320.4 MPa, 256.7 MPa and 17.6%, respectively; Vickers hardness is 104.7, and conductivity is 21.9 MS/m. For 470℃/1 h solution treatment followed by pre-aging at 65℃, impact energy along the direction of extrusion and perpendicular to that are 52.1 J and 45.9 J, respectively, and for the direct two-stage aging, impact energy along the direction of extrusion and perpendicular to that are 43.5 J and 38.8 J, respectively. The distribution of precipitates inside the grains and at the grain boundaries are more finely dispersed within the extension of pre-aging time. Precipitates at the grain boundaries are discontinuous.关键词
7020铝合金/预时效/拉伸性能/冲击韧性/显微组织Key words
7020 aluminum alloy/pre-aging/tensile properties/impact toughness/microstructure分类
矿业与冶金引用本文复制引用
杨涛,叶凌英,刘胜胆,单朝军,王国玮,陈敏,邓运来,张新明..预时效对7020铝合金组织与性能的影响[J].中南大学学报（自然科学版）,2017,48(3):578-584,7.基金项目
国家重点研发计划项目(2016YFB0300901) (Project(2016YFB0300901) supported by the National Key Research and Development Plan Program of China) （2016YFB0300901）
