TiC_x/Ni_3Al复合材料相界面显微结构及界面纳米硬度与弹性模量分布

INTERFACIAL MICRO STRUCTURE AND DISTRIBU- TIONS OF NANOHARDNESS AND MODULUS NEAR INTERFACE OF TiCx/NiAl COMPOSITES

采用SEM,EDS等对融渗工艺制备的C/Ti比x分别为0.6、0.7、0.8和0.9的四种不同TiCx/Ni3Al复合材料进行了研究,证实Ti元素向金属相存在较强的扩散,而Ni和Al元素几乎没有向陶瓷相中扩散,扩散的结果形成了两相界面之间直接的原子结合,增加了复合材料相界面结合的强度和韧性.利用纳米压痕技术研究了复合材料相界面附近的纳米硬度H和弹性模量E,二者在相界面附近均呈连续梯度分布特征,并且TiC0.7/Ni3Al复合材料在界面处具有较高的纳米硬度值.

The morphologies and the elements diffusion status of TiCx/Ni3Al composites with four C/Ti ratios fabricated by pressureless melt-infiltration processing were studied using SEM and EDS. The TiCx particle size decreased with the C/Ti ratio increasing from 0.6 to 0.9. The strong diffusion of Ti from the ceramic phase to the intermetallic resulted in enhancement of the interfacial strength owing to the atomic bonding at the interface. The mechanical properties at the interfaces of TiCx/Ni3Al composites were investigated using the nanoindentation technique. It was found that the nanohardness and the elastic modulus from the phase TiCx to the Ni3Al are a gradient distribution. As x increased from 0.6 to 0.9, elastic modulus at the interface decreased and the interfacial nanohardness reached its higher value at x equal to 0.7.