Preparation of Ti 3 AlC 2 matrix composites by selective laser melting combined with pressureless sintering

Abstract

Selective laser melting (SLM) has the ability to net complex-shaped structures. In this study, Ti₃AlC₂ matrix composites were fabricated by SLM and pressureless sintering of an Al–TiO₂–TiC–CNT system. The results show that the formation process of the sample during SLM involved the in-situ reaction of Al with TiO₂ to form TiAl₃ and Al₂O_3. TiAl₃ subsequently reacted with TiC to synthesise Ti₃AlC₂ during the pressureless sintering process. Results also show that variations of the laser power had a correlated effect on the element, and by increasing or decreasing the laser power three distinctive areas could be seen on the sample: the TiAl₃/TiC composite area, the unreacted area and alumina area according to the phase composition. As the laser power increased, the TiAl₃/TiC composite area increased, the unreacted area decreased and the chemical reaction between the material components became more sufficient. The laser power also had a significant influence on the surface topography of the SLM sample. When the laser power increased from 40 to 60 W, the surface morphology of the sample evolved from the initial disordered network to the mutually stacked structure perpendicular to the scanning direction and eventually became uniformly distributed.