The influence of Cu, Mg and Ni on the solidification and microstructure of Al-Si alloys

4th International Conference on Advances in Solidification Processes

材料科学;物理学

Darlapudi, A.^1 ; McDonald, S.D.^1 ; StJohn, D.H.^1

Centre of Advanced Materials Processing and Manufacturing, University of Queensland, St Lucia

QLD

4072, Australia^1

关键词: Commercial purity;    Eutectic silicon;    Final microstructures;    Growth morphology;    Intermetallic phase;    Modified conditions;    Nucleation and growth;    Nucleation frequencies;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/117/1/012022/pdf
DOI  :  10.1088/1757-899X/117/1/012022

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The influence of alloying elements (Cu, Mg, and Ni) on eutectic nucleation, eutectic grain morphology and the final microstructure of an Al-10Si commercial purity alloy in unmodified and Sr-modified conditions was investigated. It was found that the nucleation and eutectic grain growth morphologies of both the unmodified and Sr-modified Al-Si eutectic were significantly influenced by the addition of ternary alloying elements to a degree dependent on when the intermetallic phase formed during the solidification of the alloy with respect to the Al-Si eutectic. In cases where an intermetallic phase nucleated prior to the onset of the Al-Si eutectic reaction, the eutectic nucleation frequency was affected by changes to the available nuclei population. In cases where the intermetallic nucleated after the Al-Si eutectic, segregation of the ternary solutes in front of the Al-Si eutectic interface changed the nucleation and macroscopic growth dynamics. The changes in nucleation and growth dynamics of the Al-Si eutectic due to the presence of solute altered the morphology of the eutectic silicon considerably. This study has revealed a number of insights into the mechanisms of nucleation and growth of the Al-Si eutectic.