(蘭州理工大學(xué) 甘肅省有色金屬新材料重點實驗室，蘭州 730050)
摘 要: 用XRD和EBSD對等通道角擠壓(ECAP)過程中純銅(99.9%)的晶粒取向變化進行研究，對擠壓后的組織和晶粒取向變化機理進行分析。結(jié)果表明：純銅經(jīng)路徑A擠壓時，隨著應(yīng)變量的增大，晶粒在細化的同時原始 織構(gòu)逐漸減弱，材料均勻性提高；從小角度向大角度晶界轉(zhuǎn)變過程中，晶界取向差分布的峰值不斷向大角度晶界的均值(40°)移動，逐漸呈現(xiàn)正態(tài)分布特征，取向差梯度逐漸減小；擠壓過程中，織構(gòu)的形成是動態(tài)過程，存在“織構(gòu)起伏”效應(yīng)，其強度和方向與材料的應(yīng)變狀態(tài)密切相關(guān)。認為“織構(gòu)起伏”效應(yīng)是材料晶體結(jié)構(gòu)、晶界特征以及晶粒聚集狀態(tài)在一定的溫度和外力作用下的綜合應(yīng)變反映；材料內(nèi)部新織構(gòu)的產(chǎn)生與消失是晶群在受到外力作用后偏聚方向發(fā)生變化、內(nèi)應(yīng)力向相鄰晶界傳遞的過程中，原來的聚集狀態(tài)被破壞所致。
關(guān)鍵字: 等通道角擠壓；電子背散射衍射；晶粒取向；晶界取向差分布；織構(gòu)起伏
pure copper during equal channel angular pressing
（Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology,
Lanzhou 730050, China）
Abstract:The polycrystalline samples of pure Cu (99.9%, mass fraction) were processed at room temperature by equal-channel angular pressing (ECAP). The microstructure and its changing mechanism after ECAP were investigated by X-ray diffraction (XRD) and electron backscattered diffraction (EBSD). The results indicate that when the pure copper is extruded by route A, with the increase of strain, the original texture decreases coupled with the grains refinement, and the distribution uniformity of copper is improved. With the increase of the fraction of high-angle grain boundaries (HAGBs), the peak of misorientation moves to the typical value (40°), gradually becomes normal distribution, and the misorientation gradient decreases. The formation of texture shows a texture fluctuation effect when ECAP is a dynamic process, the direction and strength of which are closely related to the strain of the material. The texture fluctuation effect is the integrated reflection of crystal structure，grain boundary character, aggregation state at a certain temperature and under the action of forces. The external force acting on crystal class then makes the segregation orientation change, in the process of internal stress transmited on the neighboring grain boundaries, the aggregation state is broken, which cause the new texture of the material interior to vanish or appear.
Key words: equal channel angular pressing; electron back-scattered diffraction; grain orientation; grain boundary misorinetation distribution; texture fluctuation
