二次时效对Al-Cu-Mg合金组织及性能的影响

doi:10.3901/JME.2022.04.102

摘要/Abstract

摘要： 二次时效(T6I4)处理工艺即在单级时效的欠时效时间点改变时效温度，对合金进行低温二级时效处理。二次时效处理能够改善Al-Cu-Mg合金的微观组织，适当提高其力学性能以及耐腐蚀性能。通过硬度测量、剥落腐蚀性能测试、晶间腐蚀性能测试、应力腐蚀开裂测试、扫描电镜和透射电镜观察，研究二次时效对Al-Cu-Mg合金组织及性能的影响。经试验得出，经二次时效处理后，由于Al-Cu-Mg合金的晶内形成了细小弥散的θ'相，此时S相θ'相同时均匀弥散分布于基体中，采用170℃时效2 h再在经过100℃时效30 h二次时效的Al-Cu-Mg合金在力学性能上优于传统单级时效处理，并且耐蚀性能也得到显著提升，抗拉强度、伸长率、维氏硬度、剥落腐蚀等级、晶间腐蚀深度和应力腐蚀开裂指数分别为490 MPa、8.5%、156.3 HV_0.5、EA、98.6 μm和0.220。

关键词: Al-Cu-Mg合金, 二次时效, 显微组织, 耐蚀性能

Abstract: The secondary aging treatment (T6I4) is to change the aging temperature at the under-aging time point of single-stage aging, and carry out low temperature second-stage aging treatment on the alloy. The microstructure, mechanical properties and corrosion resistance of an Al-Cu-Mg alloy can be appropriately improved by the secondary aging treatment. The microstructures and properties of an Al-Cu-Mg alloy with the secondary aging were investigated by hardness measurement, exfoliation corrosion text, intergranular corrosion test, stress corrosion cracking test, observations through scanning electron microscope and transmission electron microscope. The experimental results show that the mechanical properties of an Al-Cu-Mg alloy aged at 170 ℃ for 2 h and then aged at 100 ℃ for 30 h are better than those of the traditional single-stage aging treatment and the corrosion resistance is also significantly improved, which due to the formation of fine and dispersed θ' phase in the crystal of an Al-Cu-Mg alloy and S phase θ' is uniformly distributed in the matrix after the secondary aging treatment. The tensile strength, elongation, Vickers hardness, exfoliation corrosion grade, intergranular corrosion depth and stress corrosion cracking index were 490 MPa, 8.5%, 156.3 HV_0.5, EA, 98.6 μm and 0.220, respectively.

Key words: Al-Cu-Mg alloy, secondary aging, microstructures, corrosion resistance

中图分类号:

TG166

苏睿明, 贾咏馨, 胡诗扬, 曲迎东, 李荣德. 二次时效对Al-Cu-Mg合金组织及性能的影响[J]. 机械工程学报, 2022, 58(4): 102-110.

SU Ruiming, JIA Yongxin, HU Shiyang, QU Yingdong, LI Rongde. Effects of Secondary Aging on Microstructure and Properties of Al-Cu-Mg Alloy[J]. Journal of Mechanical Engineering, 2022, 58(4): 102-110.

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