摘要
采用拉伸试验、电导率测试和透射电镜分析等方法研究了7050厚板在185℃回归再时效过程中的析出行为,并与T6时效工艺进行了比较研究。结果表明,7050-T6的合金强度较高(屈服强度约为507 MPa),但其耐应力腐蚀性能较差,电导率仅为16.59 MS/m。经回归处理后,合金的力学性能呈上升后下降的趋势,电导率呈现总体上升的趋势。当回归处理1h时,7050-RRA合金的屈服强度提升至523 MPa,电导率达到20.07 MS/m,综合性能优异。TEM结果表明,T6处理后,基体强化相主要为GP(I)区和η′相;随着回归时效进行,GP(Ⅰ)区开始转变为GP(Ⅱ)区和η′相,η′相逐渐增多使强度上升至峰值;回归处理4h后,GP区基本消失,η′相开始转变成η相,合金强度下降。
The precipitation behavior of the 7050 thick sheet during the RRA process at 185 ℃ was analyzed by tensile test,conductivity test and transmission electron microscopy（TEM）observation,and it was compared with that of 7050-T6 ones.The results indicate that 7050-T6 alloy possesses high strength,such as the yield strength of 507 MPa,and low stress corrosion resistance,such as low conductivityof 16.59 MS/m.During the retrogression process,strength of the alloy is increased firstly and then decreased with the increase of electric conductivity through the whole process.As retrogressed at185 ℃for 1h,the 7050-RRA exhibits excellent comprehensive performance,where yield strength is increased to 523 MPa and electric conductivity is 20.07 MS/m.The TEM observation reveals that the main strengthening phase is GP（I）zone andη′in the 7050-T6 alloy.During the RRA process,the GP（I）zone is transformed into GP（Ⅱ）zone andη′,and the further precipitation ofη′results in the strength increase to a peak value.Then,retrogressed to 4h,the GP zone disappears and the transition ofη′→ηcauses the decrease of strength.
作者
孙刚
梁春霞
崔建忠
虞朝智
杜旭初
孙进宝
Sun Gang Liang Chunxia Cui Jianzhong Yu Chaozhi Du Xuchu Sun Jinbao(Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education, Northeastern University School of Physics, Beijing Institute of Technology Beijing Institute of Aeronautical Materials Beijing Advanced Engineering Technology and Application Research Center of Aluminum Materials)
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2017年第9期929-932,共4页
Special Casting & Nonferrous Alloys
关键词
7050铝合金
回归再时效
微观组织
力学性能
7050Alloy
Retrogression and Re-Aging（RRA）
Microstructure
Mechanical Properties
