<i>In Situ</i> Reaction Synthesis and Mechanical Properties of V ₂ AlC

Abstract

A dense V 2 AlC ceramic was synthesized by an in situ reaction/hot pressing method using V, Al, and C powders as starting materials. The reaction path was investigated. It was found that V 2 AlC was produced by a reaction between Al 8 V 5 and C. Single ‐phase V 2 AlC could be prepared using the optimized molar ratio of V:Al:C=2:1.2:0.9. The grain sizes of as‐prepared V 2 AlC samples were temperature dependent. On increasing the temperature from 1400° to 1700°C, the mean grain size of V 2 AlC increased from 49 μm in length and 19 μm in width to 405 μm in length and 106 μm in width. The V 2 AlC sample sintered at 1500°C exhibited the highest flexural strength of 289 MPa and a fracture toughness of 5.7 MPa·m 1/2 , while the V 2 AlC sample prepared at 1400°C showed the highest compressive strength of 742 MPa. The sample sintered at 1700°C possessed the highest damage tolerance. Additionally, V 2 AlC could retain a high degree of Young's modulus up to 1200°C. Below 800°C, V 2 AlC showed excellent thermal shock resistance.