一种细晶强化金属材料新方法的研究

晶粒细化是提高金属材料综合力学性能的重要手段之一，通常采用的方法有添加细化剂、快速凝固、振动凝固等铸造方法，以及等通道挤压、累积叠轧焊、异步轧制等塑性变形方法。本文提出一种将剪切变形与传统挤压变形合二为一的挤压方法——不对称挤压方法，即将挤压模口设置在偏离中心的位置上，利用挤压时的较大静水压力和不对称挤压时的剪切变形来细化金属的组织。试验以2A12和2A50铝合金为研究对象，分析研究了不对称挤压前后试样的内部组织、力学性能以及制品的表面质量，考察不对称挤压法的可行性，从而探讨一种可工业化生产的细化组织、提高强度、改善韧性的新的挤压方法。

Research on a new method of grain refinement of metal materials

Grain refinement is an extremely effective method to improve strength and ductility of metal materials at the same time.In general,the ways to refine the grain is including the followings: rapid solidification,equal channel angular extrusion,asymmetry rolling bonding and so on.In this paper,a new method combining the shearing and extrusion into a deformation processing to refine the grain,which is named Asymmetric Extrusion,is proposed.In other words,the extrusion hole is designed on a place of deviating from the center of the extrusion die.The 2A12 and 2A50 aluminum alloys are employed to observe the microstructural evolution,mechanical properties and surface quality of materials according to the normal extrusion and Asymmetry Extrusion in this investigation.And also,the feasibility of the Asymmetry Extrusion is suggested based on the experimental results.