纤维预热温度对真空气压浸渗连续SiC_f/Al复合材料致密度和力学性能的影响

Effects of fiber preheating temperature on density and mechanical properties of continuous SiC_f/Al composites manufactured by vacuum pressure infiltration

选用先驱体法制备的直径10~15μm束丝SiC纤维作为增强体材料，采用真空气压浸渗法制备了SiCf体积分数为40%的连续SiCf/Al复合材料，研究纤维预热温度对复合材料显微组织与力学性能的影响。结果表明：复合材料中原局部存在少量团聚的SiC纤维束随着纤维预热温度的提高，纤维团聚减少，分布更趋于均匀；而复合材料致密度和抗拉强度随纤维预热温度的升高先逐渐增加后缓慢降低；其中，在纤维预热温度为500℃、浸渗温度为730℃、浸渗压力为7 MPa和保压时间为5 min的浸渗工艺条件下所制备的连续SiCf/Al复合材料的致密度为97.24%，抗拉强度达到768.9 MPa。

The vacuum pressure infiltration was performed for the continuous SiCf/Al composites with the volume fraction of SiC f being 40%, of which the reinforced material is SiC fiber with the diameter of 10-15μm fabricated by precursor method. The effects of fiber preheating temperature on the microstructure and mechanical properties of continuous SiCf/Al composites were studied. The results show that the distribution of the partial fiber reunited in the composite tends to be more uniform, while the density and tensile strength increase first and then reduce with increasing the fiber preheating temperature. Moreover, the density and tensile strength of the continuous SiCf/Al composites increase up to 97.24%and 768.9 MPa when the preheating temperature, infiltration temperature, impregnation pressure and dwell time of the fiber are set as 500℃, 730℃, 7 MPa and 5 min, respectively.