J. Phys. III France
Volume 2, Numéro 11, November 1992
Page(s) 2225 - 2238
DOI: 10.1051/jp3:1992242
J. Phys. III France 2 (1992) 2225-2238

Tensile fracture and shear localization under high loading rate in tungsten alloys

H. Couque, J. Lankford and A. Bose

Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78228-0510, U.S.A.

(Received 7 October 1991, revised 9 July 1992, accepted 15 July 1992)

The influence of loading rate and microstructure on the tensile and compressive failure properties of three microstructurally dissimilar tungsten alloys has been investigated. Dynamic tensile fracture properties were characterized through fracture toughness tests performed at a stress intensity loading rate of 106 MPa $\sqrt{{\rm m}}$ s -1, and by tensile testing at a strain rate of 103 s -1. Shear banding phenomena were investigated by means of compression tests performed at strain rates of $5 \times 10^3$ s -1. Under rapid loading conditions, nickel-cobalt-tungsten alloys were found to be tougher than nickel-iron-tungsten alloys ; the tungsten/tungsten interface was identified as the governing microstructural factor. Quantitative micromodeling using simple fracture models was found to provide a mean of correlating toughness with microstructures. Compression-induced shear localization was found to be facilitated within systems characterized by either elongated tungsten particles or an adiabatic shear-prone matrix. The shear band width was observed to be proportional to tungsten particle size.

© Les Editions de Physique 1992