(1. 中南大学 材料科学与工程学院 有色金属材料科学与工程教育部重点实验，长沙 410083；
2. 郴州强旺新金属材料有限公司，郴州 423000)
摘 要: 采用正交实验法和金相、力学性能、扫描电镜、能谱等测试手段对自主研发的变形Al-Si-Cu-Mg合金进行固溶和时效强化研究，并探究热处理过程中其组织特征的变化规律。结果表明：通过固溶(495 ℃，90 min，水冷)和时效(170 ℃，4 h，空冷)处理后，合金的硬度提高31.3%，强度提高3.3倍。固溶过程中，大量Si、Cu和Mg原子固溶于基体中，起到强烈的固溶强化作用；过剩的共晶Si逐渐发生明显粒状化；剩余的大块θ相和Q相发生球化。时效过程中，细小针状强化相θ″和细小板条状Q′相在基体的(100)面上大量析出，分布均匀，对合金起到强烈的沉淀强化效果；过剩Si主要通过扩散附着于共晶Si表面析出。
关键字: 变形铝合金；固溶；时效；正交实验；力学性能
（1. Key Laboratory of Non-ferrous Materials Science and Engineering, Ministry of Education,
School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Chenzhou Qiangwang New Metal Materials Co., Ltd., Chenzhou 423000, China）
Abstract:Solid solution and aging treatments of a novel wrought Al-Si-Cu-Mg alloy were investigated with orthogonal experiment and several other test methods, including OM, mechanical test, SEM and energy spectrum analysis, etc. Meanwhile, the variation regularities of the microstructure characteristics during this process were explored. The results show that, by solution (495 ℃, 90 min, water-quenching) and aging (170 ℃, 4 h, air-cooling) treatment, the hardness and the tensile strength of the alloys are improved by 31.3% and 3.3 times, respectively. During the solid solution, a large number of Si, Cu and Mg atoms dissolve into the matrix, resulting in a strong solid solution strengthening. The excessive eutectoid Si develops into granule, as well as the remanent big bulks of θ and Q phases. Moreover, during the aging, fine needle-shaped θ″ phase and fine lath-shaped Q′ phase precipitate from the (100) plane of the matrix uniformly and dispersively, leading to an enormous precipitation strengthening effect. Additionally, the excessive Si atoms precipitate primarily on the surfaces of the eutectoid Si by diffusion.
Key words: wrought aluminum alloy; solid solution; aging; orthogonal experiment; mechanical properties
