Experimental Studies On Phase Interface Of Ti-Ni-Cu Ternary System

The migration of phase interface in diffusion bonding is up to the diffusion anddissolution of atoms at the interface, so it is very important to research the diffusion of atomsat different phase interface. The Ti-Ni-Cu diffusion triple specimens were made by rivetingmethod to research the interface behavior. After a series of heat treatment under differentconditions, diffusion zones between the components are formed from the compact contact ofthe bulks of the components. The microstructure characteristics of the diffusion zones werestudied by means of optical metallography and SEM backscattering technique. The resultsshow that the diffusion phenomena at triple points in the specimens are affected by themechanical technics of preparing specimens. With the help of the X-ray PhotoelectronSpectroscopy, phase diagram as well as thermaodynamics calculation, it has been shown thatthere are binary and ternary intermetallic compounds simultaneously near the triple crunodewhen the Ti-Ni-Cu diffusion triple are annealed at 700℃for 200 hours. There are fourintermetallic compounds at Ti-Ni interface, and their arrangement from Ti to Ni isTi2Ni,TiNi,CuNi3Ti2 and TiNi 3.There are five intermetallic compounds at Ti-Cu interface andtheir arrangement from Ti to Cu is Ti2Cu+α-Ti,TiCu,Ti3Cu4,TiCu2 and TiCu4. There is aTiNiCu at the triple crunode.The interfaces between diffusion layers and matrix are regular and clear at Ti-Cu and Ti-Ni interfaces, and there are 3 intermetallic phases in Ti-Ni interface while 6 intermetallicphases in Ti-Cu interface when the Ti-Ni-Cu diffusion triple specimens are annealed at 700℃for 200 hours. The interfaces between diffusion layers and matrix are vague at Cu-Niinterface far away from the triple crunode, and there are solid solution in this zone. It hasbeen seen that the diffusion layers become thick when the temperature is high, which allowsexponential relationship, and the diffusion layers become thick when the annealing time islong, which allows a parabolic relationship. The inborn order of the phases in the diffusionlayers is not only influenced by the heat of formation, but also by the concentration of atomsat the interfaces.