Microstructure and compression properties of in situ dual phase nanosized (TiB2-Ti5Si3)/TiAl matrix composites fabricated by combustion synthesis and hot press consolidation

Abstract

The dual phase nanosized (TiB2-Ti5Si3)/TiAl composites were successfully fabricated using in situ method of combustion synthesis and hot press consolidation. The effects of proportions of the in situ dual phase nanoparticles (TiB2 and Ti5Si3) on microstructures and compression properties of the composites were investigated. Compared with the monophase TiB2 and Ti5Si3 particles, dual phase TiB2-Ti5Si3 particles exhibit more obvious grain refinement effect. The grain size of TiAl alloy was refined from ∼66 to ∼12 mm with the the generation of dual phase TiB2-Ti5Si3 particles. Moreover, the TiAl matrix composites reinforced with dual phase nanosized TiB2-Ti5Si3 particles exhibit better comprehensive compression properties. When TiB2:Ti5Si3 = 2:1[S(TiB2 + Ti5Si3) = 4 vol.-%], the TiAl matrix composite has a high true fraction strain of 26.1%, a true yield strength of 761 MPa and an ultimate compression strength of 1647 MPa.