热处理工艺对Al-6.5Zn-2.3Mg-2.5Cu-0.1Zr-0.2Sc合金组织和力学性能的影响

doi:10.13251/j.issn.0254-6051.2024.07.042

摘要/Abstract

摘要： 为了满足高速列车关键零部件的轻量化需求,开发Al-Zn-Mg-Cu-Zr-Sc系铸造铝合金。熔炼铸造了Al-6.5Zn-2.3Mg-2.5Cu-0.1Zr-0.2Sc合金,并对其进行了均匀化处理及固溶时效(T6)处理。对T6态合金在室温和200 ℃拉伸性能测试,并用光学显微镜、扫描电镜和透射电镜等手段对其微观组织特征进行表征。结果表明,在120 ℃时效10 h时,晶内析出相主要为GP区。随着时效时间的增加,部分GP区转变成η′相,在时效22 h时能够明显观察到η′相的存在,在时效34 h时,部分η′相逐渐长大转变成粗大的η相。200 ℃拉伸试验结果表明,22和34 h时效态合金的抗拉强度分别为617.7和575.9 MPa,屈服强度分别为600.5和560.7 MPa,断裂机制均为韧性断裂。

关键词: Al-Zn-Mg-Cu-Zr-Sc合金, 热处理, 析出相, 力学性能

Abstract: An Al-6.5Zn-2.3Mg-2.5Cu-0.1Zr-0.2Sc cast aluminum alloy for the lightweight requirements of key components for high-speed trains was developed. The Al-6.5Zn-2.3Mg-2.5Cu-0.1Zr-0.2Sc alloy was melted and cast, and homogenization treatment and solution and aging(T6) treatment was carried out. The tensile properties of the T6 state alloy were tested at room temperature and 200 ℃, respectively, and their microstructure characteristics were characterized by means of optical microscope, scanning electron microscope and transmission electron microscope. The results show that when aged at 120 ℃ for 10 h, the main precipitates within the grain are the GP region. As the aging time increases, GP regions transform into η′ phase, and the η′ phase can be clearly observed when aged for 22 h. As extending the aging time to 34 h, the η′ phase gradually grows and transforms into the coarse η phase. The results of tensile tests at 200 ℃ show that the tensile strengths of the alloy aged for 22 h and 34 h are 617.7 MPa and 575.9 MPa, respectively, and the yield strengths are 600.5 MPa and 560.7 MPa, respectively, and both the fracture mechanisms are ductile fracture.

Key words: Al-Zn-Mg-Cu-Zr-Sc alloy, heat treatment, precipitates, mechanical properties

中图分类号:

TG146.21

徐双钱, 戴志勇, 王子瑜. 热处理工艺对Al-6.5Zn-2.3Mg-2.5Cu-0.1Zr-0.2Sc合金组织和力学性能的影响[J]. 金属热处理, 2024, 49(7): 274-280.

Xu Shuangqian, Dai Zhiyong, Wang Ziyu. Effect of heat treatment process on microstructure and mechanical properties of Al-6.5Zn-2.3Mg-2.5Cu-0.1Zr-0.2Sc alloy[J]. Heat Treatment of Metals, 2024, 49(7): 274-280.

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