选区激光熔化Al-Si合金组织特征及腐蚀行为研究进展

Research progress on corrosion behavior and microstructure of Al-Si alloys produced by selective laser melting

摘要:

选区激光熔化(selective laser melting, SLM)制备的Al-Si合金在航空航天材料定制化和轻量化的发展中有着巨大潜力。然而,影响SLM成形件寿命的腐蚀行为尚未引起广泛关注。本文结合当前文献报道,根据SLM过程中的凝固特征分析了冶金缺陷和微观组织的形成原因,结合传统铸造Al-Si合金在含氯化合物中的腐蚀机理,进一步论述了SLM制备的Al-Si合金的腐蚀机理,归纳总结了冶金缺陷、微观组织和热处理工艺对于腐蚀行为的影响。发现试样的致密度,表面状态(粗糙度)和共晶Si的含量、形态及分布对腐蚀性能有重要影响。在此基础上,指出了目前SLM工艺下Al-Si合金腐蚀研究中存在的工艺参数不够系统,忽视Mg,Fe等元素的作用,研究手段和范围不够完善等不足以及未来进一步发展的方向。

Abstract:

Al-Si alloys prepared by selective laser melting (SLM) have great potential in the development of aerospace materials customization and lightweight. However, corrosion behavior affecting the life of SLM forming parts has not been widely concerned. Based on current literature reports, this paper analyzed the formation reasons for metallurgical defects and microstructure according to solidification characteristics in the SLM process. Combined with the corrosion mechanism of traditional casting Al-Si alloy in chlorine compounds, the corrosion mechanism of Al-Si alloy prepared by SLM was further discussed. The effects of metallurgical defects, microstructure, and heat treatment on corrosion behavior are summarized. It is found that the relative density, surface topography (roughness) of the sample, eutectic Si content, morphology, and distribution has important effects on corrosion performance. On this basis, it is pointed out that the existing technological parameters in the corrosion research of Al-Si alloy under the SLM process are not systematic, the effects of Mg, Fe, and other elements are ignored, the research methods and scope are not perfect, and the future development direction.