(1. 徐州工程學(xué)院 機(jī)電工程學(xué)院，徐州 221018；
2. 中國(guó)礦業(yè)大學(xué) 機(jī)電工程學(xué)院，徐州221116；
3. 高端工程機(jī)械智能制造國(guó)家重點(diǎn)實(shí)驗(yàn)室，徐州 221004)
摘 要: 為提高傳統(tǒng)ECAE工藝的擠壓效率和變形效果，提出一種具有“球形分流”結(jié)構(gòu)的新型等通道球形轉(zhuǎn)角擠壓工藝。采用DEFORM-3D有限元軟件對(duì)工業(yè)純鋁ECAE-SC變形過(guò)程進(jìn)行模擬，研究金屬流動(dòng)、擠壓載荷、等效應(yīng)變以及平均應(yīng)力的分布及變化規(guī)律；在自行設(shè)計(jì)的ECAE-SC模具上成功實(shí)現(xiàn)工業(yè)純鋁室溫單道次連續(xù)變形，對(duì)變形組織進(jìn)行了EBSD分析和顯微硬度測(cè)試。結(jié)果表明：ECAE-SC模具外角處球狀圓弧的平滑過(guò)渡有效改善底部金屬流動(dòng)性，坯料經(jīng)球形轉(zhuǎn)角依次發(fā)生剪切、膨脹和擠壓等3種不同形式的復(fù)合變形，擠壓載荷表現(xiàn)出“急劇上升-緩慢增加-穩(wěn)定變形”的變化趨勢(shì)；1道次ECAE-SC變形后，坯料內(nèi)部平均累積塑性應(yīng)變高達(dá)3.07，沿長(zhǎng)度方向形成1個(gè)近似平行四邊形的穩(wěn)定應(yīng)變區(qū)，變形均勻性良好；工業(yè)純鋁坯料經(jīng)室溫1道次ECAE-SC變形后，外形完整、表面光滑、宏觀無(wú)裂紋；材料內(nèi)部形成大量細(xì)長(zhǎng)的剪切變形帶，晶粒破碎和細(xì)化現(xiàn)象明顯，平均顯微硬度大幅提高，由初始36.6 HV增加至58.7 HV。
關(guān)鍵字: 等通道球形轉(zhuǎn)角擠壓；球形分流；有限元分析；變形行為；顯微組織；力學(xué)性能
（1. School of Mechanical and Electrical Engineering, Xuzhou University of Technology, Xuzhou 221018, China;
2. School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou 221116, China;
3. State Key Laboratory of Intelligent Manufacturing of Advanced Construction Machinery, Xuzhou 221004, China）
Abstract:In order to improve the extrusion efficiency and deformation quality of traditional ECAE process, a novel technique named equal channel angle extrusion with spherical cavity (ECAE-SC) was proposed, which has the characteristics of “spherical split-flow”. The finite element simulation of commercially pure aluminum during ECAE-SC process was carried out using DEFORM-3D software. The variation and distribution of metal flow, extrusion load, equivalent strain and mean stress during ECAE-SC process were investigated. Moreover, commercially pure aluminum was successfully processed after 1 pass of ECAE-SC at room temperature on the self-designed die with continuous deformation. The electron back scattered diffraction (EBSD) was used to evaluate the microstructure of commercially pure aluminum, and microhardness tests were conducted for the processed billet. The results show that the smooth transition of spherical arc on the outer corner of ECAE-SC die can effectively improve the metal flow at the bottom. During ECAE-SC process, the billet undergoes shear, expansion and extrusion with continuous deformation when it passes through the spherical corner, the load presents a characteristic of “sharp increase - slow increase - steady deformation”. The average equivalent strain reaches up to 3.07 after a single pass of ECAE-SC, a stable strain region approximately to a parallelogram forms along the length direction, with a reasonable level of strain uniformity. After 1 pass of ECAE-SC, the extruded billet is free of macro crack with intact shape and good surface quality, lots of shear bands are generated leading to the significant grain refinement and fragmentation. The average value of microhardness is drastically increased from 36.6 HV to 58.7 HV.
Key words: equal channel angular extrusion with spherical cavity; spherical split-flow; finite element analysis; deformation behaviors; microstructure; mechanical property
