Accession Number : AD0780777

Title :   An Investigation of the Plastic Fracture of High-Strength Steels,

Corporate Author : NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER ANNAPOLIS MD

Personal Author(s) : Cox,T. B.

Report Date : JUN 1974

Pagination or Media Count : 49

Abstract : The mechanisms of plastic fracture (dimpled rupture) in high-purity and commercial 18 Ni, 200 grade maraging steels and quenched and tempered AISI 4340 steels have been studied. Plastic fracture takes place in the maraging alloys through void initiation by fracture of titanium carbonitride inclusions and the growth of these voids until impingement results in coalescence and final fracture. The fracture of AISI 4340 steel occurs by nucleation and subsequent growth of voids formed by fracture of the interface between manganese sulfide inclusions and the matrix. The sizes of nonmetallic inclusions are an important aspect of the fracture resistance of these alloys, since void nucleation occurs more readily at the larger inclusions and that void growth also proceeds more rapidly from the larger inclusions. (Modified author abstract)

Descriptors :   *Steel, *Fracture(Mechanics), Impurities, Defects(Materials), Crack propagation, Carbides, Nitrides, Sulfides

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE