(南昌航空大学 轻合金加工科学与技术国防重点学科实验室,南昌 330063)
摘 要: 采用搅拌摩擦加工(FSP)方法对添加不同聚四氟乙烯(PTFE)含量混合粉末(PTFE+Ni)制备Ni/Al复合材料。采用SEM、EDS、XRD及EPMA对复合区微观组织进行分析,采用室温拉伸试验对Ni/Al复合材料力学性能进行测试。结果表明:在一定范围内,随着PTFE含量的增加,Ni/Al复合材料的均匀性逐渐提高,且增强相生成量逐渐增加;当PTFE含量达到7%时,其拉伸强度达到233 MPa,较添加纯镍制备Ni/Al复合材料拉伸强度(163 MPa)提升了42.9%;当PTFE含量超过7%时,部分PTFE裂解放出大量的热量,使得Al与PTFE发生反应生成AlF3和不同的铝化物,导致局部Al-Ni反应过程中Al含量不足,部分Ni未反生反应,减少了Al3Ni金属间化合物生成物的数量,使得拉伸强度下降。
关键字: 搅拌摩擦加工;PTFE;复合材料;原位反应
(National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063, China)
Abstract:Ni/Al composites were fabricated by friction stir processing (FSP) through adding different amounts of (PTFE+Ni) mixed powders to Al substrate. The microstructures of the composite zone were analyzed by SEM and EDS, the phase composition was examined by XRD, the element distributions of the composite zone were analyzed by EPMA, and the mechanical properties of the composites were tested by tensile test at room temperature. The results show that, within a certain range, the uniformity of composites increases with increasing the amount of PTFE and the number of Al3Ni intermetallic compound will be increased. When PTFE content reaches 7%, the tensile strength of composites reaches 233 MPa, compared with the composites with pure Ni (its tensile strength is 163 MPa), the tensile strength of composites with 7% PTFE increases by 42.9%; when PTFE content exceeds 7%, the reaction degree between Al and Ni increases because the PTFE cracked will produce lots of heat, at the same time, different aluminide and AlF3 are produced. The agglomerations of Ni are found because the amount of partial Al decreases. As the reaction degree between Al and Ni decreases, the number of Al3Ni intermetallic compounds decreases, as well as the tensile strength.
Key words: friction stir processing; PTFE; composites; in-situ reaction