(1. 廣東工業(yè)大學(xué) 機(jī)電工程學(xué)院，廣州 510006；
2. 廣東省特種設(shè)備檢測(cè)研究院，中山 528400；
3. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
4. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 針對(duì)經(jīng)過90°模具、8道次等通道轉(zhuǎn)角擠壓的純銅，采用電子背散射電子衍射(EBSD)和透射電鏡(TEM)分析大范圍內(nèi)加工路徑對(duì)其顯微組織演變的影響。每個(gè)路徑按照道次間棒料繞其長(zhǎng)軸轉(zhuǎn)動(dòng)角度(χ)進(jìn)行定義，角度變化范圍為0°~180°。EBSD所測(cè)大角度晶界比例和晶粒大小結(jié)果表明，當(dāng)χ=90°時(shí)晶粒細(xì)化效率最高，χ=180°時(shí)晶粒細(xì)化效率最低。該趨勢(shì)得到TEM結(jié)果的進(jìn)一步佐證。對(duì)比EBSD和TEM結(jié)果還發(fā)現(xiàn)，在定量比較ECAE材料的顯微組織差異時(shí)，應(yīng)該充分考慮晶粒組織形貌的非等軸特征。
關(guān)鍵字: 純銅；等通道轉(zhuǎn)角擠壓；劇烈塑性變形；應(yīng)變路徑；晶粒細(xì)化
（1. School of Electro-Mechanical Engineering, Guangdong University of Technology, Guangzhou 510006, China;
2. Guangdong Institute of Special Equipment Inspection and Research, Zhongshan 528400, China;
3. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
4. Key Laboratory of Nonferrous Metal Materials Science and Engineering,
Ministry of Education, Central South University, Changsha 410083, China）
Abstract:An experimental study of the microstructures in pure copper billets processed by 8 passes of equal channel angular extrusion (ECAE) via an extended range of processing routes with a 90° die is carried out. Each processing route is defined according to the inter-pass billet rotation angle (χ), which varies from 0° to 180°. According to the generation of high-angle boundaries and reduction of grain size by electron backscatter diffraction (EBSD) measurements, the grain refinement is found to be most efficient for route with χ=90° and least efficient with χ=180°, among the seven routes studied. This trend is supported by supplementary transmission electron microscopy (TEM) measurements. Comparison of the EBSD and TEM data reveals the importance of considering the non-equiaxity of grain structures in quantitative assessment of microstructural differences in ECAE-processed materials.
Key words: pure copper; equal channel angular extrusion; severe plastic deformation; strain path; grain refinement
