Some observations of ductile void growth and crack propagation in alpha zirconium

Abstract

Abstract Tensile tests have been carried out on zirconium at 77°K to study the effects of unloading on ductile crack propagation and at 77°, 295° and 423°K and to examine the influence of matrix deformation characteristics on void growth rates. The effects of unloading are considered in terms of the relaxation at the crack tips and estimates of the increased work necessary to propagate such relaxed cracks are consistent with the observed increases in fracture stress. The process of void growth was studied metallographically and changes in void dimensions were measured as a function of specimen strain. These studies indicate that the strain increments at the void tips are most important in the void growth process and that the void growth rate increases with increasing deformation temperature. Resume Afm d'etudier les effets de dechargement sur la propagation ductile des fissures a 77°, 295° et 423°K et d'examiner l'influence de la deformation de la matrice sur la vitesse de croissance des vides, des essais...