深冷处理时间对3102 H18铝箔组织及力学性能的影响

Influence of cryogenic treatment time on microstructure and mechnical properties of 3102 H18 alloy

以3102 H18铝箔为对象,研究其在液氮中保温不同时间后的室温组织和性能。结果表明,深冷5min后抗拉强度由233 MPa增加到263 MPa,硬度明显提高,延伸率变化不大;随着深冷保温时间的延长,强度和硬度变化不大,但延伸率小幅上升,到24h达到处理前的1.5倍。组织观察表明,经5min深冷处理可促使第二相析出,随保温时间增加,析出量增加有限;深冷5h后,纤维晶粒开始碎化,保温至24h,全部碎化为尺寸为0.3～2.5μm的细晶。

In the paper, the microstructures and the properties of 3102 aluminum foils which are cryogenic treated at different times are investigated. The results show that, after 5min cryogenic treatment, the tensile strength is improved from 233-263MPa and the micro-hardness is obviously enhanced, but there is no obvious change in elongation. With the increase of cryogenic treatment time,the strength and the hardness remain stable, however, the elongation is improved slightly and it is 1.5 times that of originality after 24h cryogenic treatment. TEM and XRD analysis show that second phase precipitates out in the alloy with 5min cryogenic treatment, and further to increase the cryogenic treatment time, the precipitated quantity is finite. With 5h cryogenic treatment, the grains begin to break into much smaller ones. After 24h cryogenic treatment, the grains are fully broken into close grain with the grain size of 0. 3-2. 5um.