Experimental investigation on delayed failure of alumina under shock compression

Abstract

A series of plate impact experiments have been conducted on alumina specimens with different thicknesses through the light gas gun in order to further investigate the delayed failure phenomenon under shock loading. With the aid of the velocity interferometer system for any reflector, an evident recompression signal has been observed in the temporal curve of the rear free surface velocity of the specimen, which indicates the generation of the failure wave. According to the experimental results, the failure wave propagation was probed. The results show that the failure wave generates a delayed time of ∼0·105 μs behind the shock wave front and propagates into the stressed body with a velocity of ∼5051 m s⁻¹ under the impact stress of 7·16 GPa. The physical mechanism of the failure wave was further discussed.

Keywords:

• Alumina ceramic
• Shock compression
• VISAR
• Failure wave
• Delayed failure

This work was supported by the National Natural Science Foundation of China (grant nos. 11072276 and 10802105) and the National Key Basic Research and Development Plan of China (grant no. 2011CB612211).