(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083；
3. 中南大学 有色金属先进结构材料与制造协同创新中心，长沙 410083；
4. 东北轻合金有限责任公司，哈尔滨 150060；
5. 郑州轻金属研究院，金属材料研究所，郑州 450041)
摘 要: 采用浸入式末端淬火方法，结合硬度和室温拉伸测试、光学显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)分析等手段，研究了淬火速率对16 mm厚7136铝合金挤压板材微观组织和力学性能的影响。结果表明：淬火速率大于15.0 ℃/s时，硬度和强度随淬火速率的减小缓慢降低。淬火速率小于15.0 ℃/s时，硬度和强度随淬火速率的减小迅速降低。随淬火速率减小，在(亚)晶界和晶内Al3Zr上形核析出η相的数量和尺寸增加，时效后η′强化相的数量减少，降低了硬度和强度。根据不同淬火速率时(亚)晶界和晶内Al3Zr上淬火析出相的比例分析了它们对淬火敏感性的贡献。淬火速率在4.8~41.6 ℃/s范围内，(亚)晶界对淬火敏感性的贡献更大；淬火速率约为3.0 ℃/s时，晶内Al3Zr粒子对淬火敏感性的贡献超越(亚)晶界。
关键字: 7136铝合金；淬火敏感性；力学性能；时效
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Non-ferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China;
3. Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center, Central South University, Changsha 410083, China;
4. Northeast Light Alloy Company Ltd, Harbin 150060, China;
5. Department of Light Metal, Zhengzhou Light Metal Research Institute, Zhengzhou 450041, China）
Abstract:The influence of quenching rate on the microstructure and mechanical properties of 16mm thick extruded 7136 aluminum alloy plate was studied by means of immersion end-quenching technique, hardness test, tensile test at ambient temperature, optical microscopy(OM), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results show that the hardness and strength decrease slowly with the decrease of quenching rate when the quenching rate is higher than 15 ℃/s, and decrease rapidly when the quenching rate is below 15 ℃/s. As the quenching rate decreases, the number and sizes of η precipitates at (sub)grain boundaries and on Al3Zr dispersoids in grains increase, and the number of η′ hardening precipitates decreases after aging, leading to lower hardness and strength. The contribution of (sub)grain boundaries and dispersoids to quench sensitivity at different quenching rates was analyzed based on the ratio of quench-induced precipitates associated with them. In the range of 4.8-41.6 ℃/s, (sub)grain boundaries make major contribution to quench sensitivity. At 3.0 ℃/s, the contribution of Al3Zr dispersoids exceeds that of (sub)grain boundaries.
Key words: 7136 aluminum alloy; quench sensitivity; mechanical properties; aging
