7075铝合金固溶后延迟时效对组织及力学性能的影响
Influence of Delayed Aging after Solution Treatment on the Microstructure and Mechanical Properties of 7075 Aluminum Alloy
DOI: 10.12677/ms.2025.1512237, PDF,    科研立项经费支持
作者: 韩 冰：中南大学材料科学与工程学院，湖南 长沙；江苏江顺精密科技集团股份有限公司，江苏 无锡；张 勇*：中南大学材料科学与工程学院，湖南 长沙；山东省高强韧铝合金型材与技术重点实验室，山东 临沂；张振峰：江苏江顺精密科技集团股份有限公司，江苏 无锡；杨 毅：陕西飞机工业(集团)有限公司，陕西 汉中；徐严谨：中国航空制造技术研究院金属材料技术研究所，北京
关键词: 7075铝合金；力学性能；位错密度；MgZn2相；7075 Aluminum Alloys； Mechanical Properties； Dislocation Density； MgZn2 Phase
摘要: 本文研究了7075铝合金在固溶处理后经延迟时效工艺下的显微组织演化及力学性能变化。通过对固溶后自然时效0~40 d的硬度变化规律进行系统分析，确定自然时效30 d为典型延迟时效状态，并与固溶后直接人工时效状态进行对比研究。结果表明，固溶后经自然时效30 d再进行人工时效的样品，其抗拉强度和屈服强度均较固溶后直接人工的时效低，但塑性较高。EBSD结果显示，三种状态下7075铝合金均呈现明显的纤维状长条晶粒形貌，平均晶粒尺寸差异较小，分别为2.92 μm、2.91 μm和2.99 μm。KAM分析表明，延迟时效工艺能有效调控局部应变分布与位错密度，固溶后自然时效30 d再人工时效的样品的平均KAM值为0.69，介于固溶态(0.59)与直接人工时效态(0.76)之间。结合位错密度计算结果(1.03 × 1015、1.21 × 1015、1.33 × 1015 m−2)，可推断自然时效引起的原子偏聚和初生GP区形成影响了MgZn2相的析出行为。综合分析表明，延迟时效过程对合金组织及析出相调控具有显著影响，为高强铝合金热处理工艺的优化设计提供了理论依据。
Abstract: This study investigates the microstructural evolution and mechanical property changes of 7075 aluminum alloys subjected to a delayed aging process after solution treatment. The hardness evolution during natural aging after solution treatment for 0~40 days was systematically analyzed, and a 30-day natural aging condition was selected as the representative delayed aging state for comparison with the direct artificial aging condition after solution treatment. The results show that the specimen subjected to natural aging for 30 days followed by artificial aging exhibits slightly lower tensile and yield strengths, but improved ductility compared with the direct artificial aging specimen after solution treatment. EBSD observations reveal that all three states of 7075 aluminum alloys display a distinct fibrous elongated grain morphology with comparable average grain sizes of 2.92 μm, 2.91 μm, and 2.99 μm, respectively. KAM analysis indicates that the delayed aging process effectively regulates local strain distribution and dislocation density; the average KAM value of the specimen with solution treatment and artificial aging after natural aging for 30 days (0.69) lies between that of the solution-treated state (0.59) and the directly aged state (0.76). Combined with dislocation density calculations (1.03 × 1015, 1.21 × 1015, and 1.33 × 1015 m−2), it is inferred that atomic clustering and the formation of initial GP zones during natural aging influence the precipitation behavior of the MgZn₂ phase. Overall, the results demonstrate that delayed aging significantly affects the microstructural evolution and precipitation behavior of the alloy, providing theoretical guidance for optimizing the heat treatment process of high-strength aluminum alloys.
文章引用：韩冰, 张勇, 张振峰, 杨毅, 徐严谨. 7075铝合金固溶后延迟时效对组织及力学性能的影响[J]. 材料科学, 2025, 15(12): 2226-2234. https://doi.org/10.12677/ms.2025.1512237

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