(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院 有色金屬材料科學(xué)與工程教育部重點實驗，長沙 410083；
2. 郴州強(qiáng)旺新金屬材料有限公司，郴州 423000)
摘 要: 采用正交實驗法和金相、力學(xué)性能、掃描電鏡、能譜等測試手段對自主研發(fā)的變形Al-Si-Cu-Mg合金進(jìn)行固溶和時效強(qiáng)化研究，并探究熱處理過程中其組織特征的變化規(guī)律。結(jié)果表明：通過固溶(495 ℃，90 min，水冷)和時效(170 ℃，4 h，空冷)處理后，合金的硬度提高31.3%，強(qiáng)度提高3.3倍。固溶過程中，大量Si、Cu和Mg原子固溶于基體中，起到強(qiáng)烈的固溶強(qiáng)化作用；過剩的共晶Si逐漸發(fā)生明顯粒狀化；剩余的大塊θ相和Q相發(fā)生球化。時效過程中，細(xì)小針狀強(qiáng)化相θ″和細(xì)小板條狀Q′相在基體的(100)面上大量析出，分布均勻，對合金起到強(qiáng)烈的沉淀強(qiáng)化效果；過剩Si主要通過擴(kuò)散附著于共晶Si表面析出。
關(guān)鍵字: 變形鋁合金；固溶；時效；正交實驗；力學(xué)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
