Influence of Interface Energy on Creep Rupture

Grain boundary cracking

“…Tipler and McLean [49] compared the creep behavior of copper and a Cu-0.3 at. pct Sb alloy and found that the alloy had significantly decreased creep ductility and greatly increased grain boundary porosity, compared with pure copper.…”

Homogenized finite elastoplasticity and damage: theory and computations

“…(31) with the selected values gives c ¼ 544 J/m 2 . For a purely elastic separation process in a segregated Cu-0.2wt.%Sb grain boundary, previous experiments (Inman et al, 1963;Tipler and McLean, 1970) suggest an elastic fracture energy of c 0 ¼ [2 · surface energy ) grain boundary energy] % 1.37 J/m 2 . However, we argue that our assumption of c=c 0 % 10 2 -10 3 is a reasonable one, due to the occurrence significant plastic dissipation within the cohesive zone (Freund and Hutchinson, 1985;Rice and Wang, 1989;Wei and Hutchinson, 1999).…”

“…Grain boundary segregation of antimony, as well as other solutes such as sulfur, phosphorous, and tin, often leads to intergranular brittleness in normally ductile metals such as copper and certain nickeland iron-based alloys (Rice and Wang, 1989;Mast et al, 1999). The reduction in ductility has been attributed to a decrease in surface energy accompanying an increase in local solute concentration at the grain boundaries (Tipler and McLean, 1970;Rice and Wang, 1989). Grain boundary embrittlement via solute segregation is a prominent damage mechanism in high temperature conditions that promote diffusion of the segregating elements, and has been shown to accelerate grain boundary cavitation and eventual creep rupture in Cu-1wt.%Sb (Staley and Saxena, 1990).…”

Antimony-induced embrittlement of [011] symmetric tilt boundaries in copper bicrystals

“…Although the shapes of the s f Ϫ u and f Ϫ u curves at 77 and 773 K are similar to one another, the fracture stresses and strains at 773 K are evidently smaller than those at 77 K. The observed lower fracture strain at 773 K may imply the additional contribution of cavitation process to grain-boundary embrittlement at elevated temperature. [16] The s f Ϫ u and f Ϫ u curves show local peaks near u ϭ 70.5 deg (⌺3) and u ϭ 129.5 deg (⌺11). However, no peaks are observed at misorientation angles corresponding to the other low-⌺ boundaries, e.g., u ϭ 109.5 deg (⌺3) and u ϭ 50.5 deg (⌺11).…”

“…Tipler and McLean [16] examined the influence of additions of Sb to Cu on the grain-boundary cavitation processes involved in creep tests at 673 to 773 K. They showed that the Sb addition to Cu accelerated the amount of cavitations due to bubble-type cavities. This also may contribute to the intergranular embrittlement of Cu and the misorientation dependence at high temperatures in Figure 7.…”