Accession Number : AD0682096

Title :   METALLOGRAPHIC FEATURES OF EXPLOSIVELY PRODUCED SPALL FRACTURES IN A LOW-CARBON STEEL,

Corporate Author : DEFENCE STANDARDS LABS MARIBYRNONG (AUSTRALIA)

Personal Author(s) : Banks,E. E.

Report Date : 02 OCT 1967

Pagination or Media Count : 6

Abstract : Plane shock wave techniques were used to produce spall fractures in a low-carbon steel. The metallurgical features of these fractures have been studied by fractographic and metallographic techniques. At pressures greater than 130 kb, 'smooth' spall fractures are obtained as a consequence of the negative shock wave that causes fracture in this particular situation. In spite of the very high strain rates at which this type of fracture is produced, it is of a ductile nature. It is suggested that the viscous nature of material within a shock front is the cause of this behaviour. On the other hand, 'rough' spall fractures formed by normal rarefaction waves when the incident pressure is less than 130 kb, are nucleated at cementite films and can either be of a cleavage or ductile shear nature, depending on the strain rate at which they form. A qualitative estimate shows that the higher the strain rate the greater is the proportion of cleavage. (Author)

Descriptors :   (*STEEL, FRACTURE(MECHANICS)), FRACTOGRAPHY, SURFACE ROUGHNESS, FERRITES, PEARLITE, GRAIN STRUCTURES(METALLURGY), EXPLOSIVE FORMING, AUSTRALIA

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE