金属热处理 ›› 2021, Vol. 46 ›› Issue (12): 236-240.DOI: 10.13251/j.issn.0254-6051.2021.12.039

• 工艺研究 • 上一篇    下一篇

热处理制度对喷射成形7A50铝合金组织性能的影响

杨春苗1, 王淑慧1, 刘文文1,2, 李延珍3   

  1. 1.烟台南山学院 工学院, 山东 烟台 265713;
    2.烟台南山学院 轻合金加工成形实验室, 山东 烟台 265700;
    3.航鑫材料科技有限公司, 山东 烟台 265700
  • 收稿日期:2021-06-16 出版日期:2021-12-25 发布日期:2022-02-18
  • 作者简介:杨春苗(1982—),女,讲师,硕士,主要研究方向为金属材料的组织性能控制,E-mail:yangchunmiao@nanshan.edu.cn
  • 基金资助:
    山东省高等学校青创科技计划(2019KJA019)

Influence of heat treatment on microstructure and properties of spray formed 7A50 aluminum alloy

Yang Chunmiao1, Wang Shuhui1, Liu Wenwen1,2, Li Yanzhen3   

  1. 1. College of Engineering, Yantai Nanshan University, Yantai Shandong 265713, China;
    2. Light Alloy Processing Laboratory, Yantai Nanshan University, Yantai Shandong 265700, China;
    3. Hangxin Material Testing Technology Co., Ltd., Yantai Shandong 265700, China
  • Received:2021-06-16 Online:2021-12-25 Published:2022-02-18

摘要: 研究了热处理制度对喷射成形7A50铝合金微观组织和力学性能的影响,测试了显微硬度和力学性能,运用OM、SEM(EDS)和TEM(SAED)观察了微观组织。结果表明:喷射成形后的7A50铝合金,消除了枝状晶粒,晶粒尺寸细化到60~120 μm范围;预时效(PA)处理提升了7A50铝合金试样的初始硬度,但却明显降低了自然时效(NA)过程的硬化速率,12 d自然时效处理后,相比于SS+NA态,最终硬度反而降低了19 HV0.5;SS+PA+NA+BH态的试验铝合金,屈服强度和抗拉强度最高,分别达到了475 MPa和525 MPa,屈服强度的BH值达到165 MPa,伸长率降低了10%;不同热处理状态下的试样断口均具有韧性断裂的特征,断口处存在大量的韧窝。SS+PA+NA处理后,基体内的第二相尺寸细小,分布弥散,尺寸在5~15 nm范围。

关键词: 喷射成形, 7A50铝合金, 微观组织, 热处理, 性能

Abstract: Influence of heat treatment on microstructure and mechanical properties of spray formed 7A50 aluminum alloy was investigated. The microhardness and mechanical properties were tested. The OM, SEM(EDS) and TEM(SAED) were used to characterize the microstructure. The results indicate that the dendrite grains in the spray formed 7A50 aluminum alloy are eliminated, and the grain size reaches 60-120 μm. Pre-aging (PA) treatment enhances the initial hardness of the alloy and decreases the hardening rate during the natural aging (NA) process. Compared to the solid solution treated (SS)+NA state, the final hardness decreases by 19 HV0.5 after 12 days NA process. Under the SS+PA+NA+bake hardened (BH) conditions, the yield strength and tension strength of the alloy reach their peak values 475 MPa and 525 MPa respectively, the BH value of yield strength is 165 MPa, while the elongation decreases by 10%. Under different heat treatment conditions, the fracture morphologies all show ductile characteristics and have a large number of dimples. After SS+PA+NA treatment, the secondary phase in the matrix is dispersed and fine, with the size ranging from 5 nm to 15 nm.

Key words: spray formed, 7A50 aluminum alloy, microstructure, heat treatment, properties

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