等通道双转角挤压工业纯钛的剧烈塑性变形行为  

Severe plastic deformation behaviors of commercially pure titanium processed by equal channel double angular pressing

作　　者：王晓溪[1] 张翔 薛克敏[3] 夏晓雷[1] WANG Xiao-xi;ZHANG Xiang;XUE Ke-min;XIA Xiao-lei(School of Mechanical and Electrical Engineering,Xuzhou University of Technology,Xuzhou 221018,China;Jiangsu XCMG Construction Machinery Research Institute Co.,Ltd.,Xuzhou 221004,China;School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]徐州工程学院机电工程学院,江苏徐州221018 [2]江苏徐工工程机械研究院有限公司,江苏徐州221004 [3]合肥工业大学材料科学与工程学院,安徽合肥230009

出　　处：《塑性工程学报》2023年第10期33-42,共10页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51905462);江苏省自然科学基金资助项目(BK20201150,BK20221212);江苏省高校自然科学研究重大项目(21KJA460007);江苏省“333高层次人才工程”培养项目。

摘　　要：针对难变形材料等通道转角挤压(ECAP)变形不均匀、表面易损伤开裂和模具内角磨损严重等问题,设计了一种新型等通道双转角挤压(ECDAP)工艺。采用Deform-3D软件对工业纯钛单道次ECDAP变形行为进行了三维有限元模拟,研究了坯料内部金属流动、挤压载荷、等效应变、平均应力、变形损伤以及模具应力的分布及变化规律,并将其与传统ECAP工艺进行对比。在此基础上,开展工业纯钛ECDAP工艺实验验证,对变形试样微观组织和力学性能进行了测试分析。结果表明,与传统ECAP相比,新型单道次ECDAP工艺实现了“一次挤压,两次剪切”的连续变形目的,可在保证坯料获得良好应变累积的前提下,降低工业纯钛挤压载荷,提高材料内部静水压力和变形均匀性,减小坯料变形损伤和模具内角磨损。单道次变形后,工业纯钛内部累积等效应变约为0.879,原始粗大晶粒受剧烈剪切发生明显细化,微观组织中存在大量的细小亚晶和一定数量的形变孪晶。同时,材料得到了显著强化,工业纯钛抗拉强度和显微硬度分别提升至433.7 MPa和174.1 HV,并表现出良好的塑韧性。Aiming at the problems of non-uniform deformation,easy surface damage cracking and serious wearing at the inner corners of die of hard-to-deformation materials during equal channel angular pressing(ECAP),a new equal channel double angular pressing(ECDAP)process was developed.Three-dimensional finite element simulation of single-pass ECDAP deformation behavior of commercially pure titanium was carried out using Deform-3D software.The distribution and variation laws of metal flow,extrusion load,effective strain,mean stress,deformation damage and die stress were investigated and compared with those of conrentional ECAP process.On this basis,the verification experiment of ECDAP process of commercially pure titanium was conducted.The microstructure and mechanical properties of the deformed specimens were tested and analyzed.The results show that compared with the conrentional ECAP process,the new single-pass ECDAP process achieves the continuous deformation goal of“one extrusion and twice shearing”,which can reduce the extrusion load of commercially pure titanium,increase the internal hydrostatic pressure and deformation uniformity of the material,and re-duce the deformation damage of the billet and the wearing at the inner corners of die on the premise of ensuring the considerable accumulated effective strain of the billet.After single-pass of deformation,the accumulate effective strain in commercially pure titanium is about 0.879.The initial coarse grains are greatly refined by intense shearing,and a large number of fine subgrains and a certain number of deformation twins appeare in the microstructure.At the same time,the material is significantly strengthened.The tensile strength and microhardness of commercially pure titanium increases to 433.7 MPa and 174.1 HV,respectively,and the material shows good plasticity and toughness.

关 键 词：等通道双转角挤压 有限元模拟 工业纯钛 晶粒细化 组织性能 

分 类 号：TG379[金属学及工艺—金属压力加工]