FRACTURE-TOUGHNESS OF COCR ALLOY PMMA CEMENT INTERFACE

An unsymmetric cantilever geometry was used experimentally to determin e the critical energy release rate values for cobalt chromium alloy -p olymethylmethacrylate cement (CoCr alloy-PRIMA) interfaces with satin finished, grit blasted, and plasma sprayed surface treatments applied to the CoCr alloy, Critical energy release rates of 0.013, 0.181, and 0.583 N/mm were found for the satin finish, grit blasted, and plasma s prayed CoCr alloy-PMMA interfaces, respectively. A finite element mode l of the experimental test specimen was used to determine the crack ti p phase angles (-8.73 degrees to -27.1 degrees) that indicated that th e tensile load applied to the specimens resulted in a tensile (mode I) and in-plane shear (mode II) loading at the crack tip, The experiment al data suggest that a satin finish CoCr alloy-PMMA interface has mini mal resistance to crack propagation when compared to grit blasted or p lasma sprayed surface treatments. (C) 1997 John Wiley & Sons, Inc. J B iomed Mater Res (Appl Biomater) 38: 211-219, 1997.