摘要
过共晶铝硅合金由于具有高耐磨性、低热膨胀系数和高比强度而广泛应用于汽车和飞机制造业。该类合金在常规铸造下易产生粗大的脆硬初生硅相,降低合金力学性能及耐磨性。而利用快速凝固技术能够有效细化硅相,制备出高耐磨的过共晶铝硅合金。过共晶铝硅合金的性能可以通过改变共晶硅和初晶硅的形态及其分布、二次枝晶胞的尺寸或臂间距等方式加以改善。目前过共晶铝硅合金的研究大多是关于控制共晶和初晶硅的形态和分布,而针对常规铸造的细化晶粒工艺只对25%(质量分数)硅含量以下的过共晶铝硅合金有明显效果,因此研究人员聚焦于能对高硅含量的过共晶铝硅合金实现晶粒细化的快速凝固技术。快速凝固技术区别于常规铸造的特点是高冷却速度,研究发现冷却速度对过共晶铝硅合金的相平衡和微观结构有着显著的影响。随着冷却速度的增加,过共晶铝硅合金的微观结构细化、化学均匀性提高、固溶度增加,形成非晶及亚稳相,极大地改善了过共晶铝硅合金的性能。根据不同快速凝固技术制备的过共晶铝硅合金,其细化的显微组织及对应的摩擦学行为也有所不同。这些差异对于完善快速凝固过程中硅晶粒形核长大机制、形态演化机制及其对过共晶铝硅合金性能影响的理论体系能够起到有效的补充作用。本文综述了快速凝固过共晶铝硅合金四种主要制备方法:衬底急冷技术、快速凝固-粉末冶金技术、喷射沉积技术和选择性激光熔化技术,分析了相关快速凝固工艺的研究现状,对比了不同工艺制备的过共晶铝硅合金的显微组织及耐磨性能,并从理论体系、性能预测和技术工艺三方面对其未来的研究方向提出了一些可行建议。
Hypereutectic Al-Si alloy is widely used in automobile and aircraft industry because of its high wear resistance,low thermal expansion coefficient and high specific strength.This type of alloy is easy to produce coarse brittle and hard primary silicon phase in conventional casting,which worsens the mechanical properties of the alloy and reduces its wear resistance.But rapid solidification technology can solve this problem.The properties of hypereutectic Al-Si alloy can be improved by changing the morphology and distribution of eutectic silicon and primary silicon,the size of secondary dendrite cell or arm spacing,etc.At present,the research of hypereutectic Al-Si alloy is mostly about controlling the morphology and distribution of eutectic and primary silicon,while the refining process of conventional casting is only for Si content below 25wt%of hypereutectic Al-Si alloy has obvious effect,so the researchers focus on the rapid solidification technology which can refine the grain of hypereutectic Al-Si alloy with high Si content.The rapid solidification technology is characterized by high cooling rate,which is different from conventional casting.With the increase of cooling rate,the microstructure refinement,chemical uniformity,solid solubility,amorphous and metastable phase formation of the hypereutectic Al-Si alloy greatly improved the properties of the hypereutectic Al-Si alloy.The microstructure and tribological behavior of the hype-reutectic Al-Si alloys prepared by different rapid solidification techniques are also different.These differences can effectively supplement the theoretical system of improving the nucleation growth mechanism,morphology evolution mechanism of silicon grains and its influence on the properties of hypereutectic Al-Si alloys during rapid solidification.In this paper,four main preparation methods of rapidly solidified hypereutectic Al-Si alloy are reviewed:substrate quench technology,rapid solidification powder metallurgy technology,spray deposition technology and selective laser melting technology.The research status of related rapid solidification technology is analyzed,and the microstructure and wear resistance of hypereutectic Al-Si alloy prepared by different processes are compared.The theoretical system,performance prediction and technology are discussedin the three aspects of technology,some feasible suggestions are put forward for its future research direction.
作者
杨文涛
何鹏飞
刘明
周永欣
王海斗
马国政
白宇
YANG Wentao;HE Pengfei;LIU Ming;ZHOU Yongxin;WANG Haidou;MA Guozheng;BAI Yu(School of Materials Science and Engineering,Xi’an University of Technology,Xi’an 710072,China;National Key Laboratory for Remanufacturing,Army Academy of Armored Forces,Beijing 100072,China;School of Materials Science and Engineering,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2021年第11期11126-11136,共11页
Materials Reports
基金
装备预研重点基金项目(61409230607)。
关键词
过共晶铝硅合金
快速凝固
显微组织
摩擦学行为
hypereutectic Al-Si alloy
rapid solidification
microstructure
tribological behavior
