Microstructure evolution and strengthening mechanism of TiC/ Ti6Al4 V composites fabricated by selective laser melting during isothermal deformation

Abstract

TiC/Ti6Al4 V titanium matrix composites were prepared by synthesising TiC particles using SLM technology to study the microstructure evolution of Ti6Al4 V alloy and TiC/Ti6Al4 V composites during isothermal deformation at 900°C and 1s−1 and the strengthening mechanism of TiC particles. The formation of TiC particles resulted in a yield strength of the composites 78 MPa higher than that of the Ti6Al4 V alloy. The acicular martensite coarsened after 15% deformation of the composite with recrystallisation beginning after 45% deformation. The lath-like α structure was refined, with dislocation slips in the α lath during the deformation of the composite. The TiC particles accumulate dislocations, transforming into subgrain boundaries to promote recrystallisation. The composite material is mainly based on grain refinement supplemented by Orowan strengthening by TiC particles.

Keywords

• TiC/Ti6Al4 V
• SLM
• high temperature compression
• EBSD