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自然时效硬化现象和烘烤硬化响应能力是影响7075铝合金加工性能和使用性能的关键。研究了固溶处理后7075铝合金的自然时效硬化现象及其对烘烤硬化能力的影响，分析了不同预时效处理对合金自然时效硬化的影响，提出了一种双级预时效处理工艺。采用X射线衍射仪、透射电镜、维氏硬度计和万能拉伸试验机等研究了合金经不同热处理后的组织和性能。结果表明:固溶处理后，7075铝合金在室温停滞过程中存在明显的自然时效硬化现象，显著降低其烘烤硬化能力;自然时效13天后，烘烤硬化增量由55 HV0.5降低到7 HV0.5;预时效处理，可以有效抑制自然时效硬化效应;120℃×10 min+160℃×10 min双级预时效处理，促进了合金中的η'过渡相的形核和长大，与基体呈■//[110]Al取向的半共格关系;双级预时效处理后，烘烤硬化处理后合金的屈服强度增量达到171 MPa，相比于120℃×20 min预时效处理的138 MPa，硬化增量提高了23.91%，同时发生塑性失稳的应变量更大。
Abstract：The natural aging hardening phenomenon and baking hardening response ability are the key factors affecting the processing and service performance of 7075 aluminum alloy.The natural aging hardening phenomenon of 7075 aluminum alloy after solution treatment and its effect on baking hardening ability were studied.The influence of different pre-aging treatments on the natural aging hardening of the alloy was analyzed,and a two-stage pre-aging treatment process was proposed.The microstructure and properties of the alloy after different heat treatments were studied using X-ray diffractometer,transmission electron microscopy,Vickers hardness tester,and universal tensile testing machine.The results show that after solution treatment,the 7075 aluminum alloy exhibits significant natural aging hardening during the room temperature stagnation process,significantly reducing its baking hardening ability.After 13 days of natural aging,the baking hardening increment decreases from 55 HV0.5 to 7 HV0.5.The pre-aging treatment can effectively suppress the natural aging hardening effect.The two stage pre-aging treatment of 120℃×10 min+160℃×10 min promotes the nucleation and growth of the η'transitional phase in the alloy,which exhibits a semi-coherent relationship with the matrix in the■//[110]Alorientation.After two-stage preaging treatment,the yield strength increment of the alloy after baking hardening treatment reaches 171 MPa.Compared with the yield strength increment of 138 MPa after 120℃×20 min pre-aging treatment,the hardening increment increases by 23.91%,and the strain inducing plastic instability of the alloy is greater.
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基本信息:
DOI：10.13289/j.issn.1009-6264.2025-0112
中图分类号:TG146.21;TG156
引用信息:
[1]宋娜,孙奥,于惠玲,等.双级预时效对7075铝合金硬化行为和组织演变的影响[J].材料热处理学报,2025,46(10):31-39.DOI:10.13289/j.issn.1009-6264.2025-0112.
基金信息:
烟台南山学院科研发展基金(2025KJ02012);烟台南山学院青年科研基金(NS2022Q13)