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针对经过90?模具、8道次等通道转角挤压的纯铜,采用电子背散射电子衍射(EBSD)和透射电镜(TEM)分析大范围内加工路径对其显微组织演变的影响。每个路径按照道次间棒料绕其长轴转动角度(χ)进行定义,角度变化范围为0?~180?。EBSD所测大角度晶界比例和晶粒大小结果表明,当χ=90?时晶粒细化效率最高,χ=180?时晶粒细化效率最低。该趋势得到TEM结果的进一步佐证。对比EBSD和TEM结果还发现,在定量比较ECAE材料的显微组织差异时,应该充分考虑晶粒组织形貌的非等轴特征。
In this paper, EBSD and TEM were used to analyze the influence of machining path on the microstructure evolution of pure copper extruded through 90 ° molds and 8 passes. Each path is defined according to the rotation angle (x) of the bar between the passes about its long axis, ranging from 0 ° to 180 °. The results of the large-angle grain boundary ratio and the grain size measured by EBSD show that the grain refinement efficiency is the highest at χ = 90 ◦ and the grain refinement efficiency is the lowest at χ = 180 ◦. This trend is further corroborated by the TEM results. Comparisons of EBSD and TEM results also revealed that non-equiaxial features of grain morphology should be taken into account when quantitatively comparing the microstructure differences of ECAE materials.