Nabarro, FRNCress, CMKotschy, P2007-06-122007-06-121996-08Nabarro, FRN, Cress, CM and Kotschy, P. Thermodynamic driving force for rafting in superalloys. Acta materialia, vol 44 (8), pp 3189-13981359-6454http://hdl.handle.net/10204/553Copyright: 1996 Acta Metallurgica Inc.Eshelby’s energy-momentum tensor is used to provide an analytical expression for the driving force for rafting in the elastic regime in a super alloy with a high volume fraction of gamma'. The structure is modeled as a simple cubic array of gamma' cubes separated by thin sheets of gamma'. During rafting, the gamma' particles are constrained to remain tetragonal prisms. For tension along a cube axis, the driving force is proportional to the product of the tension delta, the fractional difference delta of lattice parameters of gamma' and gamma and the fractional difference m of their elastic constants C(11)- C(12). As in the calculation of Pineau for an isolated spheroid, needles are formed when this product sigma delta m is positive. Two- and three-dimensional systems behave similarly. The initial plastic strain in gamma' is anelastic and in principle reversible. When the plastic strain exceeds m delta, platelets perpendicular to the stress axis are formed if the product sigma delta is negative.enModern superalloysThermodynamic driving forcesPlastic deformationPoisson contractionArticleNabarro, F., Cress, C., & Kotschy, P. (1996). Thermodynamic driving force for rafting in superalloys. http://hdl.handle.net/10204/553Nabarro, FRN, CM Cress, and P Kotschy "Thermodynamic driving force for rafting in superalloys." (1996) http://hdl.handle.net/10204/553Nabarro F, Cress C, Kotschy P. Thermodynamic driving force for rafting in superalloys. 1996; http://hdl.handle.net/10204/553.TY - Article AU - Nabarro, FRN AU - Cress, CM AU - Kotschy, P AB - Eshelby’s energy-momentum tensor is used to provide an analytical expression for the driving force for rafting in the elastic regime in a super alloy with a high volume fraction of gamma'. The structure is modeled as a simple cubic array of gamma' cubes separated by thin sheets of gamma'. During rafting, the gamma' particles are constrained to remain tetragonal prisms. For tension along a cube axis, the driving force is proportional to the product of the tension delta, the fractional difference delta of lattice parameters of gamma' and gamma and the fractional difference m of their elastic constants C(11)- C(12). As in the calculation of Pineau for an isolated spheroid, needles are formed when this product sigma delta m is positive. Two- and three-dimensional systems behave similarly. The initial plastic strain in gamma' is anelastic and in principle reversible. When the plastic strain exceeds m delta, platelets perpendicular to the stress axis are formed if the product sigma delta is negative. DA - 1996-08 DB - ResearchSpace DP - CSIR KW - Modern superalloys KW - Thermodynamic driving forces KW - Plastic deformation KW - Poisson contraction LK - https://researchspace.csir.co.za PY - 1996 SM - 1359-6454 T1 - Thermodynamic driving force for rafting in superalloys TI - Thermodynamic driving force for rafting in superalloys UR - http://hdl.handle.net/10204/553 ER -