Fabrication and Properties of Ti3AlC2-Based Ceramics by Two-Step Method

A two-step method was presented to fabricate Ti3AlC2-based ceramics. The first step was to synthesize a reactive powder, which mainly contains Ti2AlC, by pressureless sintering (PLS) in argon at 1500°C for 10 mins with a heating rate of 20°C×min-1. The second step was to hot press the powder to a bulk material at 1300°C for 60 mins. The second step not only densified the powder, but also promoted the phase transformation from Ti2AlC to Ti3AlC2. The ceramic sample prepared by this method consists of Ti3AlC2, Ti2AlC and a little amount of TiC. It has excellent mechanical properties: density is 4.26 ± 0.02 g×cm-3, flexural strength is 664.4 ± 90 MPa, Vickers hardness is 6.4 ± 0.5 GPa, and fracture toughness (KIC) is 9.9 ± 0.5 MPa m1/2. The so high values of strength and fracture toughness are never reported in any literature about this material, as far as we aware.