【摘要】 铸造金属基复合材料的凝固决定着材料的机械性能。本文中研究了凝固冷却速率对ＣＦ／Ａｌ－４．５Ｃｕ复合材料的显微组织、偏析及机械性能的影响。实验结果表明，挤压铸造ＣＦ／Ａｌ－４．５Ｃｕ复合材料凝固过程中，α－Ａｌ相首先在纤维间隙中开始形核，并逐渐向纤维表面生长，而共晶θ－Ａｌ２Ｃｕ相依附ＣＦ表面形核并长大。随着凝固冷却速率的降低，θ相的形态从块状转变为颗粒状，析出量逐渐减少，Ｃｕ元素显微偏析逐渐降低，复合材料的抗弯强度逐渐提高。另外，ＣＦ／Ａｌ－４．５Ｃｕ复合材料由于其强的界面结合力，其断裂特征为脆性断裂，断口形貌表现为平切型更多还原

【Abstract】 The solidification processing of metal matrix composites has a strong influence on their mechanical properties. In the present work, the effects of solidification cooling rate on the solidification microstructure, microsegregation and mechanical properties of CF/Al 4.5Cu metal matrix composites were investigated experimentally. The results showed that during the solidification processing of squeeze casting CF/Al 4.5Cu composites, α Al phase nucleated first in the interstice regions of CF, but eutectic θ Al 2Cu phase nucleated and grew on the surface of CF. As the solidification cooling rate decreased, crystallized quantity of θ Al 2Cu phase also decreased; its shape was changed from large block like to particle like; meantime, the microsegregation of Cu element also decreased, but the bent strength of the composites increased. Besides, because the fiber metal interface was strongly bonded in the CF/Al 4.5Cu composites, the fracture surface of the composites showed the characters of brittle fracture, and no fiber pull out was observed in any of these composites.更多还原