闭孔CNTs/Al复合泡沫搅拌摩擦焊工艺研究  

Study on Friction Stir Welding Process of Closed-Cell CNTs/Al Composite Foam

作　　者：庞秋 于海洋 胡志力[2,3] Pang Qiu;Yu Haiyang;Hu Zhili(Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,China;Hubei Key Laboratory of Advanced Technology of Automobile Components,Wuhan University of Technology,Wuhan 430070,China;Hubei Collaborative Innovation Center for Automotive Components Technology,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉科技大学冶金装备及其控制省部共建教育部重点实验室,湖北武汉430081 [2]武汉理工大学现代汽车零部件技术湖北省重点实验室,湖北武汉430070 [3]武汉理工大学汽车零部件技术湖北省协同创新中心,湖北武汉430070

出　　处：《稀有金属材料与工程》2020年第8期2845-2854,共10页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51775397);中国汽车产业创新发展联合基金(U1564202);新能源汽车科学与关键技术学科创新引智基地资助(B17034);湖北省高等学校优秀中青年科技创新团队计划项目(T201629)。

摘　　要：提出基于搅拌摩擦焊制备闭孔CNTs/Al复合泡沫新工艺,解决制备大面积闭孔复合泡沫的难题。利用扫描电镜对不同焊接旋转速度的闭孔CNTs/Al复合泡沫预制体及复合泡沫的微观组织进行分析;采用红外线测温仪对焊接过程中预制体温度分布进行研究。利用电子万能试验机对纯Al泡沫和不同孔隙率闭孔泡沫的屈服应力和平台应力进行对比。结果表明,当搅拌头旋转速度为1000 r/min时,闭孔CNTs/Al复合泡沫预制体表面平滑而致密。同时,增强体CNTs均匀分布在复合泡沫预制体横截面上。由发泡温度650,680和700℃对比可知,最佳发泡温度为680℃发泡15 min,泡孔结构均匀,孔隙趋于圆形,最大泡孔直径为0.48mm。室温压缩时,闭孔复合泡沫的应力-应变曲线表现出脆性与韧性相结合的变形特征。孔隙率为30.5%时,闭孔泡沫的屈服应力和平台应力值最大。同时,与纯Al泡沫相比,闭孔泡沫的屈服应力提高了2~2.8倍;平台应力提高了1.4~2.9倍。A new preparation process for closed-cell CNTs/Al composite foam based on friction stir welding was proposed.The microstructure and elemental composition of the CNTs/Al composite foams with different rotation speeds(1000~1300 r/min)were analyzed by scanning electron microscopy(SEM)and energy dispersive analysis(EDS),respectively.The temperature distribution of the CNTs/Al precursor foam was studied by infrared thermometer and numerical simulation.The mechanical properties of pure Al foam and the CNTs/Al composite foam with different porosities were compared and analyzed by the quasi-static compression test.The results show that when the rotation speed of the stirring is 1000 r/min,the surface of the CNTs/Al precursor foam is smooth and dense.Simultaneously,a blowing agent TiH2,a stabilization agent Al2O3 and reinforced phase CNTs are uniformly distributed on the cross section of the composite foam.The comparison between the foaming temperature of 650,680 and 700℃ shows that the optimum foaming condition is 680℃ for 15 min.Then the pore structure is uniform and mainly consists of circular pores,the maximum pore diameter is 0.48 mm and the structure of CNTs in the composite foam is relatively complete,which is well combined with the Al matrix.Infrared thermometer and numerical simulation temperature field show that the temperature gradually decreases with the increase of the distance to the center of the stirring head,and the peak welding temperature is located in the stirring head which exhibits a bowl-shaped distribution.The stress-strain curves of the CNTs/Al composite foam show the deformation characteristics combining brittleness and ductility at room temperature.When the porosity is 30.5%,the yield stress and platform stress values of the CNTs/Al composite foam are the largest.Compared with that of the pure Al foam,the yield stress of the CNTs/Al composite foam is increased by about 2~2.8 times,and the platform stress is increased by about 1.4~2.9 times.

关 键 词：搅拌摩擦焊 CNTs/Al复合泡沫 微观组织 力学性能 

分 类 号：TB383[一般工业技术—材料科学与工程]