深冷处理时间对A319合金显微组织和力学性能的影响

Effect of deep cryogenic treatment time on microstructure and tensile strength of A319 alloy

采用力学性能测试仪、光学显微镜、扫描电镜研究了深冷处理时间对A319合金显微组织和力学性能影响。结果表明,随着深冷处理时间的延长,A319合金室温拉伸强度和伸长率先增大后降低,在24 h时达到最大值,比常规热处理试样力学性能分别提高6%,42%。这主要是因为深冷处理对合金有预时效作用,随着深冷时间的延长,富铁相钝化,且大部分成细小的颗粒状,均匀分布在共晶区,大大减小了对材料性能的危害,有利于力学性能的改善。

The effect of cryogenic treatment time on mechanical properties of A319 alloy was investigated using a mechanical properties tester.Further,the microstructure of the alloy after the treatment was studied by optical and scanning electron microscopy.The tensile strength and elongation of A319 alloy at room temperature increase at first and then decrease with further increase of the cryogenic treatment time,reaching the maximum values at a holding time of 24 h.These values obtained by the cryogenic treatment are higher than those treated by the conventional heat treatment methods by 6% and 42%,respectively.This is mainly attributed to the pre-aging effect of the cryogenic treatment on the alloy.The iron-rich phase becomes passivated,most of which are divided into fine particles uniformly distributed in the eutectic region that significantly improves the mechanical properties of A319 alloy.