累积叠轧TC4合金超细晶组织的制备  

Ultra-Fine Grains Processing for TC4 Alloy by Accumulative Roll-Bonding

作　　者：王点 李仲洋 彭武贤 陈逸晖 刘国怀[1] 王昭东[1] Wang Dian, Li Zhongyang, Peng Wuxian, Chen Yihui, Liu Guohuai, Wang Zhaodong(State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《稀有金属材料与工程》2018年第10期3104-3111,共8页Rare Metal Materials and Engineering

基　　金：十三五国家重点研发计划(2016YFB0301201;2016YFB0300603);国家自然科学基金(51504060);辽宁省科学技术计划项目博士启动基金(201501150)

摘　　要：通过累积叠轧技术对TC4合金进行超细晶组织的制备,考察了TC4合金的热变形特点以及叠轧工艺窗口,研究了叠轧工艺参数和热处理制度对叠轧板材界面结合和微观组织的影响。结果表明,TC4合金的应力-应变曲线表现为动态回复特征,热模拟时在较高加热温度(≥700℃)和低应变速率(≤0.1s-1)下能够实现强烈塑性变形。对TC4合金进行叠轧界面的防氧化处理后,并在加热温度为720℃、轧制速度小于0.5m/s时,获得良好的结合界面和板材质量。累积叠轧变形过程是α/β协同变形和剪切变形综合作用的结果,组织中存在拉长的条带组织以及大量的剪切带。随着叠轧层数的增加,条带组织的间距逐渐变小,同时剪切带组织逐渐增加,在叠轧16层(变形量为93.75%)后条带间距为245 nm。热处理过程中随着加热温度的增高,溶质扩散和再结晶过程促进了界面结合并最终与基体保持一致。叠轧16层的TC4板材在700℃/60 min的热处理过程中能够实现完全再结晶,获得晶粒尺寸为300～600 nm的超细晶组织。The ultra-fine grain structure of TC4 alloy was fabricated by accumulative rolling bonding process, during which the hot deformation process and the ARB processing window were studied, and the effect of the ARB parameters and the heat treatment process on the interface bonding and the microstructure was investigated. The results indicate that the stress-strain curve exhibits dynamic recovery characteristics, and the high temperature（≥700 °C） and low strain rate（≤0.1 s^-1） can promote grain refinement and improve sheet quality. Finally, the excellent interface bonding and sheet quality can be obtained at a temperature of 720 °C and a low rolling rate（≤0.5 m/s） after the anti-oxidation treatment of the contact interface. The deformation during the ARB process is composed of the cooperation deformation of α/β grains and the shear deformation, and the elongated band structure and the shear bands are observed in the ARB processed TC4 alloy. The band structure spacing decreases gradually with the increase of the ARB layers, and the band spacing of 245 nm can be obtained through the 16 layers ARB process. With increasing heating temperature during the heat treatment, the solute diffusion and recrystallization process can promote the interfacial bonding and make it ultimately consistent with the matrix structure. Finally the ultra-fine grain size of the 16 layers ARB processed TC4 alloy is 300-600 nm at 700 °C/60 min.

关 键 词：TC4合金 累积叠轧 超细晶 界面结合 

分 类 号：TG146.23[一般工业技术—材料科学与工程]