High volume intermetallics reinforced Ti-based composites in situ synthesized from Ti-Si-Sn ternary system

Research highlights: → Ti-based composites reinforced with 20-40 vol.% eutectic Ti5Si3 or Ti3Sn + Ti5Si3 intermetallics were in situ synthesized. → Significant increase of Young's modulus and ultimate compressive strength was obtained. → Modification of the shape and interface of the intermetallic particles can further improve the mechanical properties. - Abstract: Ti-based alloys or composites reinforced with high fraction of intermetallic or ceramic phases may be good candidate for aerospace components operating under vibration and extremely difficult environments that require high strength, elasticity and damping capacity. In the present work, Ti-based composites reinforced with eutectic Ti5Si3 or Ti3Sn + Ti5Si3 intermetallics with volume fraction up to 20-40% have been synthesized from the Ti-Si-Sn ternary system, through non-consumable vacuum arc melting. The composites exhibit a hyporeutectic microstructure with primary Ti solid solution or/and Ti3Sn phases, plus an (α-Ti + Ti5Si3) eutectic. The results of room-temperature compressive test show that the composites exhibit significant increase of Young's modulus and higher ultimate compressive strength (UCS) than the Ti-Si hypoeutectic alloy, which can be attributed to the presence of intermetallics i.e. Ti5Si3 or (Ti3Sn + Ti5Si3) and the solute atom Sn in the Ti matrix. It is implied from the fractography that modification of the shape and interface of the intermetallics particles can further improve the mechanical properties of the Ti-based composites.