Thermal shock behavior of Ti3AlC2 from between 200°C and 1300°C

The retained strength and hardness of Ti3AlC2 bars quenched from 200 to 1300 C in air, water and silicone oil were investigated to study the thermal shock resistance. For samples quenched in air, the retained strength increased with increase of the temperature difference. For samples quenched in water, the retained strength could be divided into four zones, i.e., (i) no damage zone (20-300 C), (ii) strength degradation zone (300-500 C), (iii) stable strength zone (500-1000 C), and (iv) strength enhancement zone (1000-1300 C). The minimum retained strength in the third zone, which was higher than 60% of the initial strength, provided a prediction that the strength loss by thermal shock for Ti3AlC2 should be less than 40%. SEM analysis revealed that an oxide scale of alpha-Al2O3 was formed at high temperature for which the residual stress was calculated. The strength degradation in the second zone was attributed to the weakening of grain boundaries caused by water infiltration, whereas the strength enhancement for the air-quenched samples in the fourth zone was attributed to the formation of oxide scale and residual compressive stresses in the oxide layer. Damage caused by quenching in oil was between that of air and water quenching. The finite element method was used to simulate failure in bending, and the results indicated that the strength of a sample with an oxide scale was about 5-10% higher than that of a homogeneous sample.