镀TiC金刚石/铝复合材料的界面及热膨胀性能

采用气压浸渗法制备高体积分数的镀TiC金刚石/铝复合材料,通过SEM和EDS等手段对复合材料的断口形貌进行分析,并研究TiC镀层对复合材料界面和热膨胀性能的影响。结果表明:TiC镀层改善金刚石颗粒与铝合金基体之间的选择性粘结现象,断裂方式以基体断裂为主。部分TiC会被氧化成TiO2并与铝合金基体反应生成Al2O3,从而实现金刚石颗粒与铝合金基体之间良好的界面结合;TiC镀层有效地降低复合材料的热膨胀系数(CTE),增强复合材料热膨胀性能的稳定性。在体积分数相同的情况下,CTE随金刚石颗粒尺寸的减小而减小。

Interface and thermal expansion properties of TiC-coated diamond/Al composites

The TiC-coated diamond/Al composites with high volume fraction were fabricated by gas pressure infiltration.The fracture surface of the composites was analyzed by SEM and EDS,and the influence of titanium carbide coating on the interfacial bonding and thermal expansion of the composites was investigated.The results show that the TiC coating is proved to improve the selective interfacial bonding between diamond particles and Al alloy matrix,and the ductile rupture of the matrix is the main facture mechanism.Part of the TiC coating is oxidized to TiO2 and then reacts with Al to produce Al2O3 and thus to achieve the better interfacial bonding between diamond particles and Al alloy matrix.The coefficient of thermal expansion(CTE) of composites is decreased and stabilized due to the TiC coating.For the same volume fraction,the CTE of composites decreases with the decrease of the particle diameter.