Effect of spark plasma sintering temperature on the multi-scale microstructure evolution and mechanical properties of Ti2AlC/TiAl composites with network architecture
Zhen‐Bo Wang, Pei Liu, Aiqin Wang, Jingpei Xie, Bo Hou
Abstract
In the present work, Ti2AlC/TiAl composites with network architecture were fabricated by the method of spark plasma sintering (SPS) at different temperature using Ti-48Al-2Cr-2Nb pre-alloyed powders and graphene nanosheets (GNSs) as raw materials. The effect of sintering temperature on the multi-scale microstructure evolution and mechanical properties of Ti2AlC/TiAl composites with network architecture was investigated. The results showed that equiaxed γ-TiAl matrix composite reinforced with the continuous network structured micro-Ti2AlC phases could be in-situ fabricated at the sintering temperature of 1200 oC. With the increase of sintering temperature from 1200 oC to 1320 oC, the micro-Ti2AlC continuous network structure gradually transforms into the nearly continuous, quasi-continuous and semi-continuous network. While the equiaxed γ-TiAl matrix gradually transforms into duplex, nearly lamellar, fully lamellar TiAl. Meanwhile, the micro-nano Ti2AlC precipitates would be formed in the TiAl matrix when the sintering temperature exceeds 1200 oC. When the sintering temperature is 1310 oC, the near lamellar TiAl matrix composite reinforced with the quasi-continuous network structured micro-Ti2AlC phases and micro-nano Ti2AlC precipitates is obtained, and the as-prepared composite possesses the best mechanical properties at both room and high temperature due to the synthetic effect of quasi-continuous network structure, intrinsic properties of Ti2AlC and lamellar TiAl.