College of Materials Science and Engineering, Taiyuan University of Technology

【目的】为细化Mg-Al-Si合金中的粗大Mg2Si相,添加Al-5Ti-1B和稀土Y对Mg-5Al-5Si合金进行变质处理。【方法】熔炼制得不同成分的Mg-Al-Si合金,使用多种测试方法对变质前后合金成分、微观组织及力学性能进行分析,并讨论其变质机理。【结果】结果表明:在Mg-5Al-5Si合金中添加Al-5Ti-1B,初生相形貌由粗大块状转变为细枝晶状或多边形状,共晶相数量随着Al-5Ti-1B添加量的增加而减少,合金硬度显著提高,这是因为TiB2为Mg2Si提供了形核基底。当合金中添加1.0%Al-5Ti-1B时,再添加Y会使初生相尺寸进一步减小,形貌规整。当复合添加1.0%Al-5Ti-1B和1.0%Y时,初生Mg2Si相平均尺寸降低到10.2μm,形貌为细小多边形状,合金拉伸力学性能最优,稀土Y的变质机理主要为吸附毒化。

【Purposes】 In order to refine the coarse Mg2Si phase in Mg-Al-Si alloy, the Mg- 5Al-5Si alloys are modified by adding Al-5Ti-1B and rare earth Y. 【Methods】 The Mg-Al-Si al- loys with different compositions were prepared by smelting. Various means were used to analyze the composition, microstructure, and mechanical properties of alloys before and after modifica- tion, and discuss modification mechanism. 【Findings】 The results show that, adding Al-5Ti-1B to the Mg-5Al-5Si alloy transforms the morphology of the primary phase from coarse bulk to fine dendritic or polygon, the number of eutectic phases decreases with the increase of Al-5Ti-1B, while the hardness of the alloys increases significantly, which is attributed to TiB2 phase acting as the heterogeneous nucleation sites for primary Mg2Si phase. On the foundation of adding 1.0% Al-5Ti-1B, rare earth Y can further modify the size and morphology of Mg2Si. When 1.0% Al- 5Ti-1B and 1.0% Y are added together, the average size of the primary Mg2Si is decreased to 10.2 μm, the morphology of primary Mg2Si is fine polygonal, and the alloy has the best tensile mechanical properties, with the modification mechanism of rare earth Y mainly adsorption and poisoning.

太原理工大学技术开发项目(RH19200007)

康文旭,马润山,崔泽云,等.Al-5Ti-1B与Y复合添加对铸造Mg-5Al-5Si合金的影响[J].太原理工大学学报,2024,55(3):474-482.

KANG Wenxu,MA Runshan,CUI Zeyun,et al.Effect of Al-5Ti-B and Y on casting Mg-5Al-5Si Alloy[J].Jour-nal of Taiyuan University of Technology,2024,55(3):474-482.