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《稀有金属:英文版》
>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℃
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℃
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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