Effect of Mo Addition on the Wettability between Ni_3Al and TiC

The wetting angle between the liquid Ni3Al and the TiC solid matrix was measured by using a 2AP-LEITZ high temperature microscope at 1420℃ 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 17°, indicating an ideal cermet system. When Mo is added, the wetting angle gains a further decrease, lower than 11°. 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 Ni3 Al-TiC, leading to a great improvement in the wettability between Ni3Al and TiC.