| Intermetallic compouds. such as Ti3Al, Ni3Al, NiAl, FeAl, especially Ti3Al, which are of same crystalline structure and proximate lattice parameters, are expected to improve properties at elevated temperature of TiB2 ceramic.By means of SEM, EDXA and XRD, the sturcture, components and phases of the TiB2-Fe, TiB2-Fe-(3Ti+Al), and TiB2-Fe-Ti3Al cermet sintered in protective atomosphere were studied. The effects of adding 3Ti+AI or Ti3Al on the structure and properties of TiB2-Fe cermet were also dealed with. If the amount of additives being enough, whether no matter w hether in the form of 3Ti+AI or Ti3Al added, two hard phases structure of TiB2+TiC are formed in these cermets. The size of TiB2 crystallines in TiB2-Fe-(3Ti+Al) and TiB2-Fe-Ti3Al cermets are little larger than that in TiB2-Fe cermet No Ti3Al compoud is formed in TiB2-Fe- (3Ti+Al) cermet TiB2 and Ti3Al are not combined together in TiB2-Fe-Ti3Al cermet, and some Ti3Al is decompoed during sintering process. The binders in the above cermets are alloys composed of several elements. During the process, the TijAl compound in TiB2-Fe-Ti3Al mixture are decomposed and formed TiAl3 compound. If the amount of additives is not enough, no TiC, even less two hard phases structure of TiB2+TiC is found in TiB2-Fe-(3Ti+Al) cermet, but TiC and two hard phases structure of TiB2+TiC are still formed in TiB2-Fe-Ti3Al cermetthe size of TiB2 crystallines in TiB2-Fe-(3Ti+Al) and TiB2-Fe-Ti3Al cermet are little smaller than that in TiB2-Fe since that a large amount of Ti disolving into Fe liquid cause precipitating a largeamount of fine TiB2 crystallines. Some TiB2-Fe, TiB2-Fe-(3Ti+Al) and TiB2-Fe-Ti3Al cermets were manufactured, and the physical and mechanical properties were compared.TiB2-Fe cermet added alittle amount of Ti3Al or Ti and Al with nice combination of strenth and hardness, is of potential applications in future. |
