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【轻有色合金】175 ℃热暴露对7A99铝合金微观组织与力学性能的影响
发布时间:2020-09-15 文章来源:本站原创
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高文林1,2 李成龙3 孙进宝1,2 刘 惠1,2 虞朝智1,2 马正斌1,2 陆 政1,2

(1.中国航发北京航空材料研究院; 2.北京市先进铝合金材料及应用工程技术研究中心; 3.大连长丰实业总公司)

要: 通过XRDTEM与室温拉伸等测试分析手段,研究了在175 50100 h热暴露处理对T67A99铝合金微观组织与力学性能的影响。结果表明,经过175 50100 h热暴露处理后,7A99铝合金晶内析出相种类未发生变化,析出相仍然以η′相和η相为主。175 热暴露处理后,7A99铝合金晶内析出相由η′相向η相发生转变,η相尺寸长大、密度降低、晶界无析出带显著增宽。T67A99铝合金的抗拉强度为505 MPa、屈服强度为406 MPa、伸长率为12%;经175 ×50 h热暴露处理后其抗拉强度为330 MPa、屈服强度为250 MPa,分别较T6态降低了34.7%38.4%,而伸长率升至16.8%,较T6态提高40%;经175 ×100 h热暴露处理后合金的抗拉强度为305 MPa、屈服强度为225 MPa,分别较T6态降低了39.6%44.6%,而伸长率升高到20%,较T6态提高了66.7%175 热暴露处理后7A99铝合金强度降低主要是热暴露过程中大量半共格的η′相转变成为非共格的η相,导致铝基体晶格畸变程度显著降低。

关键词:热暴露处理;7A99铝合金;力学性能;微观组织

中图分类号:TG146.21TG113  文献标志码A

DOI10.15980/j.tzzz.2020.07.021


Effects of 175 Heat Exposure Treatment on the Microstructure and Mechanical Properties of 7A99 Aluminum Alloy

Gao Wenlin1,2, Li Chenglong3, Sun Jinbao1,2, Liu Hui1,2, Yu Chaozhi1,2, Ma Zhengbin1,2, Lu Zheng1,2

 (1.Beijing Institute of Aeronautical Materials; 2.Beijing Engineering Research Center of Advanced Aluminum Alloys and Application; 3.Dalian Changfeng Industrial Co., Ltd.)

Abstract: The effects of heat exposure treatment at 175 for 50 h and 100 h on the microstructure and mechanical properties of T67A99 alloy were investigated by means of X ray diffraction, transmission electron microscopy and room temperature tensile testing. The results reveal that the precipitate phases in the 7A99 alloy still consist of η′ and η phases after being exposured at 175 for 50 h and 100 h. The η′ phases in the grains are transformed into η phases at 175 for 50 h and 100 h heat exposure treatment, meanwhile the size of precipitate phase is increased with the decrease of density of precipitate phases and the increase of PFZ width. The tensile strength, yield strength and elongation of 7A99 alloy treated by T6 reach 505 MPa, 406 MPa and 12%,respectively, while those of ones exposured at 175 for 50 h are 330 MPa, 250 MPa and 16.8%, and those of T67A99 alloy exposured at 175 for 100 h are 305 MPa, 225 MPa and 20%, respectively. The mechanism is attributed to the η phases transformed from η′ phases reducing the distoration of the lattice severely. 

Key Words: Heat Exposure Treatment, 7A99 Aluminum Alloy, Mechanical Properties, Microstructure

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