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 V2AlC 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 degrees to 1700 degrees C, the mean grain size of V2AlC increased from 49 mu m in length and 19 mu m in width to 405 mu m in length and 106 mu m in width. The V2AlC sample sintered at 1500 degrees 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 degrees C showed the highest compressive strength of 742 MPa. The sample sintered at 1700 degrees C possessed the highest damage tolerance. Additionally, V2AlC could retain a high degree of Young's modulus up to 1200 degrees C. Below 800 degrees C, V2AlC showed excellent thermal shock resistance.