金属热处理 ›› 2020, Vol. 45 ›› Issue (7): 78-82.DOI: 10.13251/j.issn.0254-6051.2020.07.016

• 工艺研究 • 上一篇    下一篇

形变诱导析出对7A20铝合金组织与性能的影响

姜少婧1,2   

  1. 1. 烟台南山学院, 山东 烟台 265713;
    2. 山东南山铝业股份有限公司 国家铝合金压力加工工程技术研究中心, 山东 烟台 265700
  • 收稿日期:2020-02-28 出版日期:2020-07-25 发布日期:2020-09-07
  • 作者简介:姜少婧(1980—), 女, 讲师, 硕士, 主要研究方向为材料的组织与性能, E-mail:jiangshaojing123@163.com
  • 基金资助:
    山东省重点研发计划(2019GGX102025);山东省高等学校青创科技计划(2019KJA019)

Effect of deformation induced precipitation on microstructure and properties of 7A20 aluminum alloy

Jiang Shaojing1,2   

  1. 1. Yantai Nanshan University, Yantai Shandong 265713, China;
    2. National Engineering Research Center for Plastic Working of Aluminum Alloys, Shandong Nanshan Aluminum Co., Ltd., Yantai Shandong 265700, China
  • Received:2020-02-28 Online:2020-07-25 Published:2020-09-07

摘要: 采用光学显微镜、扫描电镜、透射电镜、X射线衍射仪和拉伸试验机等手段研究了预变形温度和预析出时间对7A20铝合金中第二相析出行为和组织性能的影响。结果表明:300~450 ℃预变形温度下析出的MgZn2相,粒子尺寸基本在0.1 μm左右,400 ℃析出的粒子数量最多,分布更均匀。不同预处理制度下,合金在400 ℃保温2 h的预析出处理后,屈服强度和抗拉强度达到最高值,分别为170 MPa和310 MPa,同时伸长率也达到20%。拉伸断口均表现为韧性断裂特征。热轧形变和预析出处理后,MgZn2析出相衍射峰主要出现在40°~45°之间。试验合金1、2和4 h预析出处理后,MgZn2相的尺寸分别为0.1~0.2、0.3~0.8和0.6~1.0 μm。第二相粒子密度随预析出时间的延长逐渐降低。

关键词: 7A20铝合金, 形变诱导析出, 微观组织, 力学性能

Abstract: Effect of pre-deformation temperature and pre-precipitation time on precipitation behavior of the second phase,microstructure and mechanical properties of 7A20 aluminum alloy was investigated by means of OM, SEM, TEM, XRD and tensile tester. The results indicate that the average size of MgZn2 phase in the tested alloy is about 0.1 μm, and the fraction of precipitation phase is the most and distributed uniformly when deformed at 400 ℃. The peak value of yield strength and tension strength of the alloy are 170 MPa and 310 MPa, respectively, after pre-precipitation at 400 ℃ for 2 h, while the elongation reaches 20%. The fracture morphologies all exhibit ductile fracture characteristics. XRD peak of MgZn2 phase precipitates exists in the range of 40°-45° after hot rolling and pre-precipitation. The size of MgZn2 phase is about 0.1-0.2 μm, 0.3-0.8 μm and 0.6-1.0 μm after pre-precipitation for 1 h, 2 h and 4 h, respectively. The density of MgZn2 phase decreases with the increase of pre-precipitation time.

Key words: 7A20 aluminum alloy, strain-induced precipitation, microstructure, mechanical properties

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