Al-Si alloys, known for their excellent castability, strength-to-weight ratio, corrosion resistance, and other characteristics, are extensively applied in the automotive, aerospace, electronic packaging and other fields. These performance characteristics are highly sensitive to the intrinsic structure, extrinsic morphology, and distribution of eutectic Si, often necessitating the use of modification techniques for microstructure control. However, the integration of related modification theories and techniques is inadequate, resulting in modified microstructures that fail to meet performance expectations or exhibit discrepancies. Given the current divergence in understanding the modification mechanisms of eutectic Si and its impact on performance, this review aims to systematically sort out the theories and technical essence behind eutectic Si modification, assess how changes in eutectic Si morphology at multiple scales affect alloy performance, thereby enhancing the comprehensive understanding and effective application of eutectic Si modification. The paper will also address current divergent cognitions by elucidating various theories of eutectic Si growth, delineating the fundamental differences between growth and modification, and correlating modification structures with mechanisms; it will also discuss effective characterization of modification structures, their multi-scale relationship with performance, and pertinent simulation techniques. Furthermore, it will also explore the impact of contemporary advanced manufacturing processes on modification. In a broader context, this paper offers a comprehensive synthesis of the current knowledge on eutectic Si modification, pinpoints areas where understanding is incomplete, and proposes recommendations for future research. By synthesizing the literature and research findings to date, this paper aims to guide future research directions, enhance the performance of Al-Si alloys, and broaden their applicability across various industrial settings.
Wu et al. (Sun,) studied this question.