界面改性对SiCf/Cu基复合材料热膨胀性能的影响

研究了SiCf/Cu基复合材料分别在有无Ti6Al4V界面改性涂层两种情况下的纵向热膨胀行为,并采用扫描电镜对热循环后的试样进行显微形貌观察。结果表明,界面结合强度对纤维增强金属基复合材料的纵向热膨胀行为有很大影响。对于没有Ti6Al4V涂层的复合材料,其热膨胀行为不稳定,在经历连续两次热循环后,其纵向均表现为正的残余应变,原因是基体发生了严重的界面脱粘、滑移和膨胀;而对于有Ti6Al4V涂层的复合材料,其纵向热膨胀系数明显减小,两次热循环后其尺寸保持稳定,纤维/基体界面结合也保持稳定。

Effect of Interfacial Modification on Thermal Expansion Property of SiCf/Cu Matrix Composites

The longitudinal thermal expansion characteristics of SiCf/Cu matrix composites without or with Ti6Al4V interlayers were studied, and the microstructures of the specimens after thermal cycles were observed by the scanning electronic microscopy. The results reveal that the interfacial bonding strength between the fiber and the matrix has significant influence on the longitudinal thermal expansion behavior of fiber-enhanced metal-matrix composites. The composites without Ti6Al4V interlayers have unstable thermal expansion behavior and exhibit positive thermal hysteresis behavior after the two continuous thermal cycles due to the interfacial debonding, sliding and expansion of the matrix. While the composites with Ti6Al4V interlayers keep dimensional stable after the two thermal cycles, and their longitudinal coefficients of thermal expansion (CTE) are greatly reduced as well as the fiber/matrix interface keeps stable.