Excellent thermal shock resistance of Al alloy-infiltrated SiC composites

摘要

The aim of this work is to improve the thermal shock resistance of SiC ceramics. A simple process of melt infiltration was adopted to introduce Al alloy into SiC ceramic and form a Ti3Si(Al)C-2 layer on the surface of the composite. Compared with the original SiC ceramic, the infiltrated composite displayed apparently enhanced thermal shock resistance resulting from the soft Al alloy and special laminated structure Ti3Si(Al)C-2. The crack initiation temperature of the infiltrated composite was 100 degrees C higher than that of the SiC ceramic. After one thermal cycle at 300 degrees C, the original SiC ceramic samples lost approximately 65% of their strength, whereas the infiltrated composite samples lost only around 35% of their strength after a thermal cycle at 400 degrees C. Furthermore, with increasing thermal cycles at 500 degrees C, the thermal shock resistance of the infiltrated composite remained superior to that of the original SiC ceramic.