Microstructure Damage of Glasses under Shock Wave Compression

Experimental measurements were conducted for the shock compressed glasses at the stresses below their Hugoniot elastic limit ( HEL ). It has been revealed that, in terms of the microstructure damage degree, there exist two different regions within the stressed samples: a compressed (without damage) and a fractured regions, respectively. Results of K9 and ZF1 glasses with double-layer structure sample demonstrate that the formation of the fracture region could be due to an activation and development of the primary microcracks on glass surface under shock wave compression, which is the first cause. Besides, due to the different compressibility between the matrix and the inhomogeneous phases distributed in the original glass body, numerous locally strained spots would be produced under shock wave compression. When the surface microcracks propagate to the strained spot boundaries, new cracks are generated, accompanying with crack turning and branching, which makes glass body further fracture of fragmentize.