论文部分内容阅读
采用透射电子显微镜、光学显微镜、拉伸力学性能测试等手段比较分析了不同固溶时效工艺对7055铝合金挤压棒材微观组织结构和力学性能的影响规律和机理。结果表明,固溶和时效工艺的合理搭配对控制合金微细结构、获得理想的综合力学性能有重要作用。采用470℃/20 min+480~490℃/20 min的两级固溶处理可以进一步减少合金中未溶化合物的数量,有利于增加时效强化效果;当第二级固溶温度为490℃时,可以使未溶化合物数量明显减小,其体积分数从单级固溶的2.5%降低至约2.0%;晶粒尺寸在30~35μm。本试验条件下,7055铝合金挤压棒材经470℃/20min+485℃/20 min两级固溶处理和随后的135℃/16 h+190℃/10 min两级时效处理,抗拉强度和屈服强度分别达到694和660 MPa,延伸率仍保持14%,合金具有最佳的综合力学性能。
The effects of different solution aging treatments on the microstructure and mechanical properties of 7055 aluminum alloy extruded bars were analyzed by transmission electron microscopy, optical microscopy and tensile testing. The results show that the proper combination of solution treatment and aging treatment plays an important role in controlling the fine structure of the alloy and obtaining the ideal comprehensive mechanical properties. The two-stage solution treatment at 470 ℃ / 20 min + 480 ~ 490 ℃ / 20 min can further reduce the amount of undissolved compounds in the alloy, which is beneficial to increase the aging strengthening effect. When the second-stage solid solution temperature is 490 ℃, Can significantly reduce the amount of undissolved compounds, the volume fraction of single-stage solution from 2.5% to about 2.0%; grain size of 30 ~ 35μm. Under the experimental conditions, the 7055 aluminum alloy extruded bar was treated by two-stage solution treatment at 470 ℃ / 20min + 485 ℃ / 20min and the subsequent two-stage aging treatment at 135 ℃ / 16h + 190 ℃ / 10min. The tensile strength And yield strength reached 694 and 660 MPa respectively, the elongation rate remained at 14%, and the alloy had the best comprehensive mechanical properties.