Synthesis and some properties of Ti3SiC2 by hot pressing of Ti, Si and C powders -: Part 2 -: Mechanical and other properties of Ti3SiC2

Some properties of the remarkable Ti3SiC2 based ceramic synthesised by hot pressing of elemental Ti, Si, and C powders have been investigated. Its flexural strength by using three point bending tests and fracture toughness by using single edge notched beam tests were measured at room temperature to be in the range 310-427 MPa and about 7 center dot 0 MPa m(1/2), respectively. This material is a relative 'soft' ceramic with a low hardness of 4 GPa. Ti3SiC2 is similar to the soft metals and is a damage tolerant material that is able to contain the extent of microdamage. An oxidation test has been performed in the temperature range 1000-1400 degrees C in air for 20 h. The oxidation resistance below 1100 degrees C was good. Two oxidized layers were formed, the outer layer consisting of pure rutile-type TiO2, and the inner layer a mixture Of SiO2 and TiO2. The average coefficient of thermal expansion (CTE) of Ti3SiC2 was measured to be 9.29 x 10(-6) K-1 in the temperature range 25-1400 degrees C. The thermal shock resistance of Ti3SiC2 was evaluated by quenching the samples from 800 degrees C, 1200 degrees C, and 1400 degrees C, respectively. The retained flexural strength drops dramatically at quenching temperature, but shows a slight increase after quenching from 1400 degrees C compared with quenching from 800 degrees C and 1200 degrees C.