Microstructure and mechanical properties of forged Al-7.1Zn-1.1Mg-1.6Cu-0.14Zr alloy after two-step ageing treatment at 120 and 170℃
来源期刊：Rare Metals2010年第4期
论文作者：WANG Shaohuaa,ZHANG Xingguoa,YANG Shoujieb,FANG Canfenga,HAO Haia,and DAI Shenglongb a School of Materials Science and Engineering,Dalian University of Technology,Dalian ,China b Beijing Institute of Aeronautical Materials,Beijing ,China
文章页码：433 - 437
摘 要：The tensile properties,electrical conductivity,and microstructure of the forged Al-7.1Zn-1.1Mg-1.6Cu-0.14Zr alloy were investigated after a two-step ageing treatment at 120 and 170℃.The results indicate that the strength of the alloy reaches the peak value at 170℃ for 1 h during the second step ageing and then decreases sharply.However,the electrical conductivity value increases continuously with the second ageing time increasing.The fracture mechanism of the alloy is intergranular fracture for 1 h and then changes to dimple transgranular fracture later,and the toughness of the alloy is improved significantly.The phases of η’ and η are major precipitates in the alloy under the two-step ageing condition.Discontinuous grain boundary precipitates and precipitate-free zones along the grain boundary are clearly observed.
WANG Shaohuaa,ZHANG Xingguoa,YANG Shoujieb,FANG Canfenga,HAO Haia,and DAI Shenglongb a School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,China b Beijing Institute of Aeronautical Materials,Beijing 100095,China
摘 要：The tensile properties,electrical conductivity,and microstructure of the forged Al-7.1Zn-1.1Mg-1.6Cu-0.14Zr alloy were investigated after a two-step ageing treatment at 120 and 170℃.The results indicate that the strength of the alloy reaches the peak value at 170℃ for 1 h during the second step ageing and then decreases sharply.However,the electrical conductivity value increases continuously with the second ageing time increasing.The fracture mechanism of the alloy is intergranular fracture for 1 h and then changes to dimple transgranular fracture later,and the toughness of the alloy is improved significantly.The phases of η’ and η are major precipitates in the alloy under the two-step ageing condition.Discontinuous grain boundary precipitates and precipitate-free zones along the grain boundary are clearly observed.
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