In situ reaction synthesis and mechanical properties of V₂AlC

A dense V₂AlC 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 V₂AlC was produced by a reaction between Al₈V₅ and C. Single -phase V ₂AlC could be prepared using the optimized molar ratio of V:Al:C=2:1.2:0.9. The grain sizes of as-prepared V₂AlC samples were temperature dependent. On increasing the temperature from 1400° to 1700°C, the mean grain size of V₂AlC increased from 49 μm in length and 19 μm in width to 405 μm in length and 106 μm in width. The V₂AlC 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 V₂AlC 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, V₂AlC could retain a high degree of Young's modulus up to 1200°C. Below 800°C, V₂AlC showed excellent thermal shock resistance.