Jin Shuoxun, Ngai Tungwai, Li Liejun, Jia Shian, Zhai Tongguang, Ke Dongjie
Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials, South China University of Technology, Guangzhou 510640, China.
Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA.
Materials (Basel). 2018 Aug 13;11(8):1422. doi: 10.3390/ma11081422.
In this study, Al-1.00 Mg-0.65 Si-0.24 Cu alloy was solution heat-treated, water-quenched, and then pre-deformed for 5% before aging. The peak hardness and yield strength of the pre-deformed sample with subsequent artificial aging were similar to that of a T6 condition sample. It was also found that the pre-deformation treatment could inhibit the negative influence of natural aging to some degree. After seven days of natural aging, the pre-deformed sample obtained better peak hardness and yield strength upon artificial aging than the sample without pre-deformation. In addition, the pre-deformation treatment could reduce 50% of the artificial aging time to reach the peak aging condition compared with T6 treatment. For the peak aged condition in the pre-deformed sample, transmission electron microscopy (TEM) observation found two types of precipitates exhibited along the dislocations besides the β″ precipitates in the Al matrix. Both precipitates had disordered atomic arrangements on the ordered subcell (Si network). The disordered precipitates occupied a number of Mg and Si atoms, resulting in less β″ precipitates formed during artificial aging at 180 °C.
在本研究中，对Al-1.00Mg-0.65Si-0.24Cu合金进行固溶热处理、水淬，然后在时效前进行5%的预变形。预变形样品随后进行人工时效处理后的峰值硬度和屈服强度与T6态样品相似。还发现预变形处理在一定程度上可以抑制自然时效的负面影响。自然时效7天后，预变形样品在人工时效时获得的峰值硬度和屈服强度优于未预变形的样品。此外，与T6处理相比，预变形处理可将达到峰值时效状态的人工时效时间减少50%。对于预变形样品的峰值时效状态，透射电子显微镜（TEM）观察发现，除了Al基体中的β″析出相外，沿位错还出现了两种析出相。两种析出相在有序亚晶胞（Si网络）上都具有无序的原子排列。无序析出相占据了大量的Mg和Si原子，导致在180℃人工时效过程中形成的β″析出相减少。
