Factors influencing formation and growth of coarse Ti-Fe compound in Ti-Fe eutectic reaction

Brittle coarse Ti - Fe compound seriously deteriorates the joint strength of Ti and stainless steel, therefore it is necessary to study the formation mechanism of coarse Ti - Fe compound. In the present work, the factors influencing the formation and growth of coarse Ti - Fe compound have been studied, primarily using the eutectic reaction method between pure Ti and pure Fe. The results show that the existence of the supersaturated beta-Ti( Fe) solid solution is a precondition for the formation of the coarse Ti - Fe compound, and the formation of supersaturated beta-Ti( Fe) solid solution is due to high process parameters. When the temperature is 1100 degrees C and the holding time is <10 s there is no supersaturated beta-Ti( Fe). Subsequently no coarse Ti - Fe compound forms in the eutectic reaction zone. However, when the joining temperature and/or prolonging the holding time is enhanced, coarse block Ti - Fe compound forms and grows after the appearance of supersaturated beta-Ti( Fe) solid solution. The formation and growth of the coarse block Ti - Fe compound can be constrained through properly controlling the process parameters ( temperature, time and exterior force) to get a comparatively thin reaction zone, which causes less supersaturated beta-Ti( Fe) solid solution.