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采用拉伸实验、硬度测试、高分辨透射电子显微镜(HRTEM)﹑扫描电镜(SEM)等方法研究了回归及回归再时效处理对喷射沉积高Zn(质量分数为12%)7000系铝合金的微观组织及力学性能的影响。结果表明,该合金经峰值时效处理(120℃×14 h)后,晶内主要强化相为GPⅡ区,晶界析出相呈连续分布;经回归处理(180℃×0.5 h)后,晶内主要强化相为较小的η’相,晶界析出相明显粗化;采用回归再时效处理(120℃×14 h+180℃×0.5 h+120℃×14 h)后,晶内析出物为亚稳定的η’相和稳定的η相,晶界析出相为不连续分布的η相;对η相高分辨像进行解卷处理,利用jems软件构建η相晶胞并模拟其高分辨像,最终确定η相各原子所在的位置。回归时效实验合金的抗拉强度达到890 MPa,伸长率为9.2%,断口为沿晶和穿晶混合断裂。
The microstructure of spray-deposited high-quality Zn (mass fraction of 12%) 7000 series aluminum alloy was studied by means of tensile test, hardness test, high-resolution transmission electron microscopy (HRTEM) and scanning electron microscope (SEM) Effect of organization and mechanical properties. The results showed that the main strengthening phase in the alloy was GP Ⅱ after the peak aging treatment (120 ℃ × 14 h), and the precipitates were continuously distributed in the grain boundary. After the recrystallization treatment (180 ℃ × 0.5 h) The precipitates in the grain boundary are obviously roughened by the smaller η ’phase of the strengthening phase and the precipitates in the grain boundary are precipitated by the regressive re-aging treatment (120 ℃ × 14 h + 180 ℃ × 0.5 h + 120 ℃ × 14 h) Stable η ’phase and stable η phase, the grain boundary precipitates are discontinuous distribution η phase; the high-resolution image of η phase unwrapping processing, the use of jems software to build η phase cell and simulate its high resolution image, the final Determine the location of η atoms each atom. The regression aging test alloy tensile strength reached 890 MPa, elongation of 9.2%, the fracture is intergranular and transcrystalline mixed fracture.