(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點實驗室，長沙 410083；
3. 中南大學(xué) 有色金屬先進(jìn)結(jié)構(gòu)材料與制造協(xié)同創(chuàng)新中心，長沙 410083；
4. 東北輕合金有限責(zé)任公司，哈爾濱 150060；
5. 鄭州輕金屬研究院，金屬材料研究所，鄭州 450041)
摘 要: 采用浸入式末端淬火方法，結(jié)合硬度和室溫拉伸測試、光學(xué)顯微鏡(OM)、掃描電鏡(SEM)和透射電鏡(TEM)分析等手段，研究了淬火速率對16 mm厚7136鋁合金擠壓板材微觀組織和力學(xué)性能的影響。結(jié)果表明：淬火速率大于15.0 ℃/s時，硬度和強(qiáng)度隨淬火速率的減小緩慢降低。淬火速率小于15.0 ℃/s時，硬度和強(qiáng)度隨淬火速率的減小迅速降低。隨淬火速率減小，在(亞)晶界和晶內(nèi)Al3Zr上形核析出η相的數(shù)量和尺寸增加，時效后η′強(qiáng)化相的數(shù)量減少，降低了硬度和強(qiáng)度。根據(jù)不同淬火速率時(亞)晶界和晶內(nèi)Al3Zr上淬火析出相的比例分析了它們對淬火敏感性的貢獻(xiàn)。淬火速率在4.8~41.6 ℃/s范圍內(nèi)，(亞)晶界對淬火敏感性的貢獻(xiàn)更大；淬火速率約為3.0 ℃/s時，晶內(nèi)Al3Zr粒子對淬火敏感性的貢獻(xiàn)超越(亞)晶界。
關(guān)鍵字: 7136鋁合金；淬火敏感性；力學(xué)性能；時效
（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
