搅拌铸造法制备短碳纤维/AZ91复合材料的组织与性能  

Microstructure and mechanical properties of short carbon fiber/AZ91 composite fabricated by stir-casting

作　　者：常海[1] 黄勇[2] 胡小石[2] CHANG Hai;HUANG Yong;HU Xiaoshi(National Center for Materials Service Safety,University of Science and Technology Beijing,Beijing 100083,China;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]北京科技大学材料服役安全科学中心,北京100083 [2]哈尔滨工业大学材料科学与工程学院,哈尔滨150001

出　　处：《复合材料学报》2019年第1期159-166,共8页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(51201006;51071057)

摘　　要：采用搅拌铸造法制备了不同体积分数(10vol%、15vol%、20vol%)的短碳纤维增强镁基(CF_s/AZ91)复合材料,并选取了三个挤压比和两个挤压温度对其进行热挤压变形,采用光学显微镜(OM)、SEM和TEM对CF_s/AZ91复合材料的显微组织进行了观察,并测试其室温力学性能及阻尼性能。研究结果表明,热挤压能够有效降低CF_s/AZ91复合材料气孔率;在热挤压过程中,纤维沿挤压方向定向排列,同时基体发生动态再结晶。随着挤压温度及挤压比的增大,晶粒呈现等轴状,组织更加均匀。CF_s/AZ91复合材料经过挤压后,其力学性能得到提高,屈服强度和抗拉强度随挤压比和CF_s体积分数的增大而增大,然而CF_s纤维在热挤压后发生明显断裂,限制了挤压态复合材料强度的进一步提升。低温低挤压比条件下,CF_s/AZ91复合材料具有较好的阻尼性能,随着挤压比及挤压温度的升高,CF_s/AZ91复合材料室温及高温阻尼性能均有所降低。The short carbon fiber(CFS)reinforced AZ91 Mg matrix composites with different CFS volume fractions(10vol%,15vol%,20vol%)were fabricated by stir-casting method.The cast CFS/AZ91 composites were extruded into bars with three different extrusion ratios at 250℃and 350℃,respectively.During the hot extrusion,grains of the AZ91 matrix are refined due to the dynamic recrystallizaiton while the CFS distribute parallel to the extrusion di-rection.With increasing of the extrusion temperature and extrusion ratio?the porosity ratio of the CFS/AZ91 com-posites is reduced effectively and the recrystalled grains grow up accompanied by the improvement of the microstruc-ture homogeneity.The tensile properties of CFS/AZ91 composites are improved due to the improved microstructure whereas the fiber fractures obviously during extrusion,which will restrict the further improvement of the mechanical properties.The CFS/AZ91 composite extruded with small extrusion ratio at lower temperature has better damping capabilities than those of the composites extruded with high extrusion ratio and higher temperature.

关 键 词：搅拌铸造 热挤压 CFS/AZ91 镁基复合材料 显微组织 力学性能 

分 类 号：TB331[一般工业技术—材料科学与工程] TG113.1[金属学及工艺—物理冶金]