(1. 贵州航天天马机电科技有限公司，遵义 563000；
2. 南昌航空大学 江西省航空构件成形与连接重点实验室，南昌 330063；
3. 哈尔滨工业大学 先进焊接与连接国家重点实验室，哈尔滨 150001)
摘 要: 实现了20 mm厚的15% SiCp增强2A14铝基复合材料搅拌摩擦对接焊，并对接头的微观组织和力学性能进行了分析。结果表明：SiCp/2A14复合材料焊接接头可以划分为四个区域，分别是母材(BM)、热影响区(HAZ)、热力影响区(TMAZ)和焊核区(NZ)。其中，BM区的组织呈现轧制条带状，该组织在HAZ受热发生了粗化；在TMAZ中，能够观察到由细小晶粒组成的挤压流线状组织；然而在NZ中，条带状组织消失，形成了均匀细小的等轴晶；并且NZ中SiC颗粒和白色相Al4C3得到充分细化，呈弥散均匀分布。接头的显微硬度最低值出现在HAZ和TMAZ的交界处，此处也是FSW接头断裂位置。接头的抗拉强度、屈服强度和断后伸长率分别为278 MPa、255 MPa和2.77%，分别达到母材的83.91%、77.62%和71.76%。通过数字图像相关法(DIC)测得接头的最大局部应变为16.8%。接头的断裂模式为韧性断裂和脆性断裂的混合断裂模式。
关键字: 搅拌摩擦焊；铝基复合材料；微观组织；力学性能
（1. Guizhou Aerospace Tianma Electromechanical Technology Co., Ltd., Zunyi 563000, China;
2. Jiangxi Key Laboratory of Forming and Joining Technology for Aerospace Components, Nanchang Hangkong University, Nanchang 330063, China;
3. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China）
Abstract:FSW butt welding was attained for the 20 mm thick plates of SiCp/2A14 reinforced aluminum matrix composite with 15% in SiC volume fraction, and the microstructure and mechanical properties of the joint were analyzed. The results show that the composite welded joint can be divided into four zones, which are the base material (BM), heat-affected zone (HAZ), thermo-mechanical affected zone (TMAZ) and nugget zone (NZ). Among them, the base material microstructure presents a rolled strip organization, which is coarsened by heat in the HAZ. In the TMAZ, the extruded streamline microstructures composed of fine grains can be observed, and the strip microstructure in the NZ disappears, and a uniformly fine equiaxed grains are formed. Moreover, the SiC particles and white phase Al4C3 in the NZ are fully refined and distributed in a diffuse and uniform manner. The lowest value of microhardness of the joint is observed at the interface of the HAZ and TMAZ, which is also the place where fracture occurs. The tensile strength, yield strength and elongation of the joints are 278 MPa, 255 MPa and 2.77%, respectively, which reach 83.91%, 77.62% and 71.76% of the BM, respectively. A maximum local strain of 16.8% at fracture is observed with digital image correlation method (DIC). The joint fracture mode is a mixed fracture mode of ductile fracture and brittle fracture.
Key words: friction stir welding; aluminum matrix composite; microstructure; mechanical property
