Samuel Ehab, Samuel Agnes M, Songmene Victor, Samuel Fawzy H
Département des Sciences Appliquées, Université du Québec à Chicoutimi, Chicoutimi, QC G7H 2B1, Canada.
Department of Mechanical Engineering, École de Technologie Supérieure (ÉTS), Montréal, QC H3A 1K3, Canada.
Materials (Basel). 2023 Aug 15;16(16):5639. doi: 10.3390/ma16165639.
The present analysis addresses the solidification and thermodynamic parameters involved during the solidification of aluminum (Al)-based alloys as presented in the literature using different systems viz., binary aluminum-boron (Al-B) and aluminum-titanium (Al-Ti) systems, ternary aluminum-titanium-boron (Al-Ti-B) and aluminum-titanium-carbon (Al-Ti-C) systems, as well as taking into consideration the silicon-titanium-aluminide (Si-TiAl) interaction in Al-based alloys containing Si. The analysis is supported by recent metallographic evidence obtained by the authors on A356.2 alloys. The sections on thermodynamic aspects cover the different models proposed concerning nucleation and growth on a newly formed Al grain. The value of the recalescence parameter reduces gradually with the increase in the Ti added. At a level of 0.20 wt%, this parameter becomes zero. If the concentration of grain refiner exceeds a certain amount, the grain size becomes minimal. Another parameter to be considered is the interaction between the grain refiner and traces of other metals in the base alloy. For example, Al-4%B can react with traces of Ti that may exist in the base alloy, leading to the reaction between boron and titanium to form titanium diboride (TiB). Grain refinement is achieved primarily with TiB rather than aluminum diboride (AlB), or both, depending on the Ti content in the given alloy.
本分析探讨了文献中所呈现的铝基合金凝固过程中涉及的凝固和热力学参数，这些参数基于不同的体系，即二元铝硼（Al-B）和铝钛（Al-Ti）体系、三元铝钛硼（Al-Ti-B）和铝钛碳（Al-Ti-C）体系，同时还考虑了含硅铝基合金中硅化钛铝（Si-TiAl）的相互作用。该分析得到了作者近期在A356.2合金上获得的金相证据的支持。热力学方面的章节涵盖了关于在新形成的铝晶粒上形核和生长所提出的不同模型。随着添加钛含量的增加，再辉参数的值逐渐降低。当含量为0.20 wt%时，该参数变为零。如果晶粒细化剂的浓度超过一定量，晶粒尺寸将达到最小。另一个需要考虑的参数是晶粒细化剂与基体合金中其他微量金属之间的相互作用。例如，Al-4%B会与基体合金中可能存在的微量钛发生反应，导致硼与钛反应生成二硼化钛（TiB）。根据给定合金中的钛含量，晶粒细化主要通过TiB实现，而非通过一硼化铝（AlB），或者两者共同作用。
