Application of an intermetallic compound Ti5Si3 to functionally graded materials.

Ti–Ti5Si3-functionally graded materials (FGMs) have successfully been fabricated by utilizing bonding through a eutectic reaction which occurs between Ti and Ti5Si3, where Ti5Si3 was employed because of its high heat and oxidation resistance. The bonding by the eutectic reaction has been investigated to bond a plate of pure Ti and of Ti5Si3 together. A compositionally and microstructurally graded region, where the volume fraction of Ti5Si3 changes continuously, has been obtained between these plates after bonding at 1613 K. Subsequently, a similar method has been utilized to make coating on Ti plates and semi-round rods through the eutectic reaction with Ti5Si3 powder. In this case, a similar compositionally and microstructurally graded region has been obtained. No macroscopic defects, including observable cracks, have been detected in these FGMs fabricated.