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。
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.
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
1997年第3期25-31,共7页
Acta Materiae Compositae Sinica
基金
国家自然科学基金
国家教委博士点基金
上海交大金属基复合材料国家实验室开放课题资助
关键词
复合材料
挤压铸造
碳纤维
金属基
凝固
composites, squeeze casting, solidification, microsegregation, bent strength, fracture
