纤维预热温度对3D-C_f/Al复合材料显微组织及力学性能的影响

Effect of fiber preheating temperature on microstructure and mechanical properties of 3D-C_f/Al composites

采用真空气压浸渗法制备纤维体积分数为51%的三维五向编织M40碳纤维增强铝基复合材料(3D-C_f/Al),研究纤维预热温度对3D-C_f/Al复合材料显微组织与力学性能的影响,并对比研究3D-C_f/Al复合材料与单向连续C_f/Al复合材料的差异。结果表明:复合材料致密度随着编织体预热温度的提高而增大,提高预热温度可有效减少复合材料内部孔洞和纤维偏聚等浸渗缺陷;复合材料的拉伸强度随纤维预制体预热温度的提高而显著降低。其中,在预热温度500℃、浸渗温度720℃、浸渗压力7 MPa和保压时间20 min的工艺条件下,所制备的3D-C_f/Al复合材料致密度为97.3%,拉伸强度为777.8 MPa,弹性模量为186.1 GPa。

The vacuum gas pressure infiltration was performedtopreparethe 3D-Cf/Al composite reinforced 3D five-directional braided performs woven by M40 graphite fiber with thefibervolume fraction of 51%. The effects of preheating temperature on the microstructure and tensile strength of 3D-Cf/Al composites were studied,and the difference between 3D-Cf/Al composites and continuous Cf/Al compositeswerecompared.The results show that the density of composite increaseswith the fiber preheat temperatureincreasing,the increase ofthe fiber preheat temperature can effectively reduce the infiltration defects,such asinternal holes and partial fiber reunited.The tensile strength reduces significantly with the fiber preform preheating temperature increasing.Moreover, the density,tensile strength and elasticity modulus of the 3D-Cf/Al compositesare97.3%,777.8 MPa and 186.1GPa, respectively,when the preheating temperature, infiltration temperature, impregnation pressure and dwell time of the fiber are 500℃, 720℃, 7 MPa and 20 min.