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采用透射电镜组织观察、DSC分析和硬度测试,研究了室温水、沸水和空气3种淬火冷却介质对Al-9.0Zn-2.5Mg-2.0Cu-0.15Zr-0.2Sc铝合金硬度和微观组织的影响。结果表明,采用室温水冷淬火T6时效后合金硬度最高、晶内细小弥散析出相最多、粗大平衡相最少,晶界无析出带(PFZ)基最窄;采用空冷淬火,T6时效后合金硬度最低、晶内析出的粗大平衡相最多,其周围约有50 nm宽的PFZ,合金的晶界PFZ最宽。Sc对合金淬火敏感性的影响取决于其抑制合金再结晶程度与Al3(Sc,Zr)粒子的分布。
The microstructure and hardness of Al-9.0Zn-2.5Mg-2.0Cu-0.15Zr-0.2Sc aluminum alloy were investigated by transmission electron microscopy, DSC and hardness tests. The effects of room temperature water, boiling water and air quenching medium on the microstructure were investigated. . The results show that the hardness of the alloy after quenching with T6 at roomtemperature is the highest, the fine precipitates are the most, the coarse phase is the least, and the PFZ group is the narrowest at the grain boundary; the hardness of the alloy is the lowest after T6 aging, Crystallization out of the coarse balance of up to about 50 nm wide around the PFZ, the grain boundary PFZ widest. The effect of Sc on the quench sensitivity of an alloy depends on its distribution of Al3 (Sc, Zr) particles that inhibits the degree of recrystallization of the alloy.