Lin Ling, Zhou Lian, Xie Yu, Bai Weimin, Li Faguo, Xie Ying, Lu Mingxin, Wang Jue
School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China.
Central Research Institute, Baoshan Iron & Steel Co., Ltd., Shanghai 201900, China.
Materials (Basel). 2022 Sep 1;15(17):6056. doi: 10.3390/ma15176056.
Hypoeutectic Al-Si-Mg alloys with a silicon content of around 10 wt % are widely used in the aerospace and automotive fields due to their excellent casting properties. However, the occurrence of "silicon poisoning" weakens the refinement effect of a conventional refiner system such as Al-5Ti-1B. In this paper, we proposed the "pre-refinement" method to avoid the "Si poisoning" to recover the refinement effect of Al-5Ti-1B. The core concept was to adjust the order of adding the Si element to form the TiAl before forming the Ti-Si intermetallic compound. To prove the effectiveness of the "pre-refinement" method, three alloys of "pre-refinement", "post-refinement", and "non-refinement" of an Al-10Si-0.48Mg alloy were prepared and characterized in as-cast and heat-treatment states. The results showed that the average grain diameter of the "pre-refinement" alloy was 60.19% smaller than that of the "post-refinement" one and 81.34% smaller than that of the "non-refinement" one, which demonstrated that the proposed method could effectively avoid the "silicon poisoning" effect. Based on a refined grain size, the "pre-refinement" Al-10Si-0.48Mg alloy showed the best optimization effect in mechanical properties after a solid-solution and subsequent aging heat treatments. The best mechanical properties were found in the "pre-refinement" alloy with 2 h of solid solution treatment and 10 h of aging treatment: a hardness of 92 HV, a tensile strength of 212 MPa, and an elongation of 20%.
硅含量约为10 wt%的亚共晶Al-Si-Mg合金因其优异的铸造性能而广泛应用于航空航天和汽车领域。然而，“硅中毒”的出现削弱了传统细化剂体系（如Al-5Ti-1B）的细化效果。在本文中，我们提出了“预细化”方法以避免“硅中毒”，从而恢复Al-5Ti-1B的细化效果。其核心概念是调整添加硅元素的顺序，以便在形成Ti-Si金属间化合物之前先形成TiAl。为了证明“预细化”方法的有效性，制备了Al-10Si-0.48Mg合金的“预细化”、“后细化”和“未细化”三种合金，并对其铸态和热处理状态进行了表征。结果表明，“预细化”合金的平均晶粒直径比“后细化”合金小60.19%，比“未细化”合金小81.34%，这表明所提出的方法可以有效避免“硅中毒”效应。基于细化的晶粒尺寸，“预细化”的Al-10Si-0.48Mg合金在固溶和随后的时效热处理后，在力学性能方面表现出最佳的优化效果。在经过2小时固溶处理和10小时时效处理的“预细化”合金中发现了最佳力学性能：硬度为92 HV，抗拉强度为212 MPa，伸长率为20%。
