20 likes | 146 Vues
Calculation of Concentrations and Fluxes in Multicomponent Diffusion Couples by a A Transfer Matrix Method (TMM) M. A. Dayananda, Purdue University —MET DMR-0304777. Fig. 1.
E N D
Calculation of Concentrations and Fluxes in Multicomponent Diffusion Couples by a A Transfer Matrix Method (TMM)M. A. Dayananda, Purdue University—MET DMR-0304777 Fig. 1 An objective of this research is to investigate diffusion in multicomponent systems. Atransfer matrixmethod (TMM) has been developed for the development of solutions for multicomponent diffusion couples. Expressions for the transfer matrix and its integral are derived so that interdiffusion fluxes and concentrations of all components can be determined at any section in the diffusion zone from the initial values of interdiffusion fluxes or concentration gradients available at some other section. Interdiffusion coefficients evaluated as average values over various regions of the diffusion zone by a method of moments are utilized. The TMM is significant because it can handle any number of diffusing components. In Fig. 1 are shown concentration profiles determined by the transfer matrix method for a ternary Cu-Ni-Zn diffusion couple assembled with disks of Alloy I (30.1Cu-44.7Ni-25.2Zn) and Alloy II (80.6Cu-19.4Ni at%) and diffusion annealed at 775°C for two days. The TMM profiles are shown to be identical with those generated from the method of Fujita-Gosting. In Fig. 2 are shown profiles generated by TMM for a quaternary Cu-Ni-Zn-Mn diffusion couple annealed for 2 days at 775oC. The generated profiles represent the experimental data points very well. Fig. 2
Calculation of Concentrations and Fluxes in Multicomponent Diffusion Couples by a A Transfer Matrix Method (TMM)M. A. Dayananda,Purdue University —MET DMR-0304777 Broad Impact and Education The applications of TMM techniques have now been incorporated in the MultiDiFlux program developed under this grant for multicomponent diffusion analysis. The various advances made in our research were presented in two invited talks and two submitted papers at the Multicomponent-Multiphase Diffusion Symposium in honor of Mysore A. Dayananda held at San Antonio TMS meeting, March12-16, 2006. As an Invited speaker at the July 2006 Physical metallurgy Gordon Conference, the PI also discussed diffusion in multicomponent systems. Recently, three technical papers were published, one in Acta Materialia and two in Journal of Phase Equilibria and Diffusion (JPED). Four papers are currently in print, one in Phil. Mag. and three in JPED. The MultiDiFlux program is currently being utilized by many researchers in other universities in Asia and Europe, in addition to many students and professors in USA.. Kevin M. Day (a Ph.D candidate) presented a poster on “Analysis of Interdiffusion in Selected High Temperature Alloy Systems”, at ASM Symposium on Modeling of Heat Treat Processes, 23rd Heat Treat Society Conference, Pittsburgh, Sept 26-28, 2005 and at the MSE Graduate Student Project Presentations at Purdue University held in October 2005.