材料期刊网

本文在540-640 ℃温度范围内, 研究了真空热压温度对15%(体积分数)SiC_p/2009Al复合材料的微观组织和力学性能的影响. 复合材料的致密度随热压温度升高而增加, 在580 ℃达到最大值, 高于580 ℃时下降.  TEM界面观察发现:热压温度为540和560 ℃时复合材料界面结合较弱, 界面出现开裂现象;当热压温 度为580和600 ℃时界面清洁、结合较好; 当温度高于620 ℃时,复合材料界面有MgAl₂O₄和Al₄C₃形成.复合材料的强度和塑性均在580 ℃取得最佳值. 拉伸断口观察发现:热压温度低于560 ℃时, 复合材料的断裂以界面脱黏为主;热压温度在580-600 ℃之间时, 复合材料以基体的韧性断裂和颗粒的断裂为主; 热压温度高于620 ℃时, 复合材料界面处MgAl₂O₄和Al₄C₃脆性相的形成使界面开裂, 复合材料的断裂为基体韧性断裂、界面开裂以及SiC颗粒断裂.

The effects of hot pressing temperature on microstructures and tensile properties of 15% (volume fraction) SiC_p/2009Al composites were investigated in this paper. The relative density of the composites increased rapidly with increasing the hot pressing temperature up to 580 ℃ and decreased with further increasing the temperatures. TEM observations revealed that the interface bonding was quite weak with the interface crack when the hot pressing temperature was below 560 ℃. When the composites were hot pressed at 580 and 600 ℃, the interface was clean and had a good interface bonding. The MgAl₂O₄ and Al₄C₃ formed at the interfaces when the hot pressing temperature was above 620 ℃. Tensile tests indicated that the composite fabricated at 580 ℃ exhibited the optimum strengtand ductility. Fractography revealed that for the composite fabricated at the hot pessing temperture below 560 ℃, the fracture mechanism was mainly the interfacial debonding. For the compositfabrcated at 580 and 600 ℃, the fracture mechanism of the composite was the matrix ductile fracture and the SiC particle fracture, When the hot pressing temperature was above 620 ℃, the interface fractured along MgAl₂O₄ and Al₄C₃, and the fracture mechanism of the composite was the matrix ductile fracture, the interface crack and the particle fracture.