(华南理工大学 国家金属材料近净成形工程技术研究中心，机械与汽车工程学院，广州 510640)
摘 要: 本文制备了不同Fe和Mn含量高真空压铸AlSiMgMn合金，使用透射电镜(TEM)对富Fe相晶体结构和成分进行了分析；使用高分辨三维X射线(3D μ-CT)对合金进行了断层扫描，获得了富Fe相三维形貌和空间坐标；结合非平衡凝固相变计算，讨论了Fe和Mn含量对富Fe相形成的影响，并分析了初生α-Fe相的生长机理。基于二分Kmeans和DBSCAN方法，设计了空间粒子团簇计算程序，对3D μ-CT得到的富Fe金属间化合物进行了聚类计算，分析了其团簇定量特征。结果表明：随着Fe含量增加，富Fe相中Fe含量增加；Mn含量增加不改变富Fe相的元素含量；两者均不改变富Fe相的晶格常数，但大幅提高富Fe相的形成温度；与平衡凝固相比，高冷却速度下富Fe相和α(Al)相形成顺序改变，对富Fe金属间化合物三维特征和分布产生重要影响，其团簇更为紧密。
关键字: 高真空压铸；AlSiMgMn合金；富Fe相；三维形貌；团簇特征
（School of Mechanical and Automotive Engineering, National Engineering Research Center of Near-net-shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510640, China）
Abstract:AlSiMgMn alloys with different Fe and Mn contents were prepared with high vacuum die-casting (HVDC) process. Transmission electron microscopy (TEM) was used to analyze and compare the crystal structure and composition of the Fe-rich intermetallic in the alloys, and their three-dimensional morphology and characteristics were inspected by high-resolution three-dimensional X-ray micro computed tomography (3D μ-CT). Combined with calculation of non-equilibrium solidification process, the influences of composition and cooling rate on the Fe-rich intermetallic formation were analyzed and discussed. The growth mechanism of primary Fe-rich intermetallic was proposed. Based on the 3D coordinates of the intermetallics, two methods of bisecting, namely Kmeans and DBSCAN, were used to characterize the clusters of the intermetallics. The results show that with the Fe content increases, the Fe content in the intermetallic increases but the intermetallic lattice constant doesn’t show difference; the increase of Mn content does not change the intermetallic compositions whereas significantly increases the formation temperature of the intermetallics promoting their formation before α(Al) grains, which causes significant change of the intermetallic three-dimensional characteristics and distribution, namely the intermetallic clusters are denser.
Key words: high vacuum die casting; AlSi10MgMn alloy; Fe-rich intermetallics; three-dimensional morphology; cluster characteristics
