Mo添加对Ni_3Al-TiC润湿特性的影响机制研究

Effect of Mo Addition on the Wettability between Ni_3Al and TiC

采用2AP-LEITZ高温显微镜对TiC-Ni3Al的润湿接触角进行了实验测定,着重探讨了Ni3Al对TiC的润湿特性以及Ni3Al中添加少量Mo的影响机制.结果表明,TiC与Ni3Al之间具有良好的润湿性能.5wt％Mo的添加使Ni3Al向TiC基板浸渗的深度增大,并与TiC颗粒发生固溶反应置换出部分Ti,在其周围形成一个含Mo的壳层.在这个壳层里,Ti、Mo进一步与Ni3Al固溶,这些反应降低了液-固表面张力,导致了润湿接触角的下降,从而改善了TiC-Ni3Al的润湿性.

The wetting angle between the liquid Ni3Al and the TiC solid matrix was measured by using a 2AP-LEITZ high temperature microscope at 1420degreesC under a flowing Ar gas atmosphere. The effect of Mo addition into Ni3Al on the wettability of Ni3Al-TiC and the effect mechanism were mainly discussed. The result shows that, the wetting angle of Ni3Al-TiC is as low as 17degrees, indicating an ideal cermet system. When Mo is added, the wetting angle gains a further decrease, lower than 11degrees. It is considered that, a small amount of Mo diffuses into the boundary of TiC particles and forms solid solution. The substituted Ti then reacts with Ni3Al in-situ. Thus decreases the tensile stress on the solid-liquid interface of Ni3Al-TiC, leading to a great improvement in the wettability between Ni3Al and TiC.