深冷处理对铝青铜微观组织与性能的影响

Effect of deep cryogenic treatment on microstructure and properties of aluminum bronze

对固溶态铝青铜（Cu-2.2%Al、Cu-4.5%Al、Cu-7%Al）进行深冷处理（Deep Cryogenic Treatment,DCT）,研究深冷时间和层错能对铝青铜微观组织、布氏硬度与拉伸性能影响。结果表明：铝青铜经深冷处理后晶粒得到细化,并形成孪晶。随着深冷时间的延长,Cu-2.2%Al、Cu-4.5%Al和Cu-7%Al铝青铜的布氏硬度先增大再减小,最后趋于平稳,在10~12 h达到峰值,分别为98.5 HBS、93.7 HBS和96.1 HBS,并建立了布氏硬度与深冷时间的关系方程。延长深冷时间可以提高铝青铜的屈服强度,但是对抗拉强度、均匀伸长率的影响差别不大。层错能对Cu-2.2%Al和Cu-4.5%Al合金的抗拉强度影响不大,但是对Cu-7%Al合金的抗拉强度提高显著;屈服强度和均匀伸长率则随着层错能的降低而升高。

Solid solution treated aluminum bronze（ Cu-2.2% Al,Cu-4.5% Al and Cu-7% Al） was processed by deep cryogenic treatment（ DCT）.Effect of the DCT time and stacking fault energy（ SFE） on microstructure,Brinell hardness and tensile properties of the aluminum bronze was investigated.The results show that grains of the aluminum bronze are refined and the twins are formed after the DCT.With the increasing of the DCT time,Brinell hardness increases first to the maximum after the DCT for 10-12 h and then decreases gradually to a stable value finally.An equation between the Brinell hardness and DCT time is established.With the increasing of the DCT time,the yield strength of the aluminum bronze is enhanced,however,no significant effect on ultimate tensile strength and uniform elongation is observed.The SFE has little effect on improving ultimate tensile strength of the Cu-2.2% Al and Cu-4.5% Al alloys,however,it significantly increases the ultimate tensile strength of the Cu-7% Al alloy.Furthermore,the yield strength and the uniform elongation of the Cu-Al alloys increases with the decreasing SFE.