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Mechanism of Degradation of Mechanical Properties of Metal Matrix Composite due to Interfacial Reaction

界面反应导致金属基复合材料力学性能下降的机理

基本信息

批准号：
01550549
负责人：
OCHIAI Shojiro
金额：
$ 1.73万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

项目摘要

In order to describe the degradation due to interfacial reaction and coating treatment in mechanical properties of metallic composites, the influence of reaction layer on room and high temperature strength of alumina fiber-reinforced aluminium composite, and mechanical interaction between coating(or reaction)layer and fiber were studied experimentally and theoretically.(A)In alumina/aluminium composite, a metallic compound CuAl_2 was formed by addition of copper element into matrix. This compound fractured in an early stage of deformation, forming crack on fiber surface, which reduced fiber strength. This phenomenon was described in a quantitative manner by calculation of energy release rate of fiber at crack-tip. On the other hand, at high temperatures, the compound behaved plastically, which decreased energy release rate, resulting in high strength of fiber. At very high temperatures, the softening of matrik caused reduction in strength of composite due to increase in critical length.(B)A new calculation method was proposed to describe the strength of fiber with coating layer. With this method, the influence of difference in elastic properties between coating layer and fiber on strength of fiber was well described. This method is useful to design the-coating treatment. The application of this method revealed that the high modulus-type carbon fiber has critical energy release rate of 3 J/m^2 and the high strength-type one 2 J/m^2 This is the first finding in this field.

为了描述界面反应和涂层处理对金属复合材料力学性能的影响，从实验和理论上研究了反应层对氧化铝纤维增强铝复合材料室温和高温强度的影响，以及涂层（或反应）层与纤维之间的力学相互作用。(A)在氧化铝/铝复合材料中，在基体中加入铜元素形成金属化合物CuAl_2。该复合材料在变形初期发生断裂，在纤维表面形成裂纹，降低纤维强度。通过计算纤维在裂纹尖端的能量释放率，定量地描述了这种现象。另一方面，在高温下，该化合物表现为塑性，这降低了能量释放率，从而导致纤维的高强度。在非常高的温度下，由于临界长度的增加，基体的软化导致复合材料强度的降低。(B)提出了一种新的描述有涂层纤维强度的计算方法。该方法较好地描述了涂层与纤维弹性性能差异对纤维强度的影响。该方法可用于涂层处理的设计。该方法的应用表明，高模型碳纤维的临界能量释放率为3 J/m^2，高强度型碳纤维的临界能量释放率为2 J/m^2，这是该领域的首次发现。