纤维预热温度对连续Al2O3f/Al复合材料力学性能的影响

选用Nextel610型Al₂O₃纤维为增强体、ZL210A连续氧化铝合金为基体，采用真空压力浸渗法制备纤维增强铝基复合材料(Al₂O_3f/Al)，纤维的体积分数为40%，预热温度分别为500、530、560和600℃，研究了纤维预热温度对Al₂O_3f/Al复合材料的微观组织、纤维损伤和力学性能的影响。结果表明：随着纤维预热温度的提高复合材料的致密度随之提高，最大达到99.2%，材料的组织缺陷最少，纤维的分布均匀；随着纤维预热温度的提高从复合材料中萃取出来的Al₂O₃纤维的拉伸强度不断降低，纤维预热温度为600℃的复合材料中Al₂O₃纤维的拉伸强度仅为1150 MPa，纤维表面粗糙，有大尺寸附着物。纤维的预热温度对Al₂O_3f/Al复合材料的拉伸强度有显著的影响。预热温度为500、530、560和600℃的复合材料其拉伸强度分别对应于298、465、498和452 MPa。组织缺陷、纤维损伤和界面结合强度，是影响连续Al₂O_3f/Al复合材料强度的主要因素。

Effect of Fiber Preheating Temperature on Mechanical Properties of Continuous Al2O3f/Al Composites

The composite materials of continuous Al₂O_3f/ZL210A alloy with 40% of Nextel610-Al₂O₃ fiber were fabricated via vacuum-pressure infiltration process, while the fiber was preheated at temperatures of 500, 530, 560 and 600℃, respectively before pressure-infiltration. The effect of fiber preheating temperature on the microstructure and mechanical properties of the composites of continuous Al₂O_3f/ZL210A alloy was investigated. The results show that the density of composites increases with the increase of fiber preheating temperature; Among others, the composite of continuous Al₂O_3f/ZL210A made out of the fiber Al₂O_3f preheated at 600℃ presents the highest density of 99.2%; The tensile strength of Al₂O₃ fibers extracted from the prepared composites depends significantly on their preheating temperature, namely the higher preheating temperature may results in the lower tensile strength, as an example, the extracted Al₂O₃ fiber, which was subjected to pre-heat treatment at 600 C, presents a rough surface morphology with tensile strength of only 1150 MPa; The fiber preheating temperature has a significant effect on the tensile strength of continuous Al₂O_3f/Al composites. Indeed, the composites fabricated with Al₂O₃ fibers, which were preheated at 500, 530, 560 and 600℃ respectively, possess corresponding tensile strength of 298, 465, 498 and 452 MPa. The existed defects and damages on fibers, as well as the interfacial reaction between fibers and the matrix may be the main factors affecting the strength of the composites of continuous Al₂O_3f/ZL210A alloy.