Comparative study of Oswald ripening and trans-interface diffusion-controlled theory models: Coarsening of γ′ precipitates affected by elastic strain along a concentration gradient Article uri icon

abstract

  • According to Lifshitz, Slyozov, and Wagner (LSW) and Trans-Interface Diffusion-Controlled (TICD) theoretical models, this paper reports the microstructure and its coarsening behavior of γ′ metastable-coherent precipitates in concentration gradient of Ni-13.75Ti (at%25)/Ni generated by diffusion couple. The coarsening of precipitates was evaluated in two different Ti contents (R1-11.4Ti (at%25) and R2-13Ti (at%25)) generated along the concentration gradient and includes average size, size distributions and growth rate. The solvus and metastable-coherent bimodal lines as determined at 850 °C of 9.16 (at%25) and 9.92Ti (at%25) respectively by scanning electron microscopy. This paper suggests that elastic strains produced by the matrix/precipitate lattice mismatch caused significant deviations between the experimental results and those predicted by the LSW or TIDC theories. Activation energies for TIDC (Qi) and LSW (Qr) are Qr: 219.69 and 172.61 kJ mol-1 for R1 and R2 regions, respectively, and Qi: 218.46 and 164.56 kJmol-1 for R1 and R2 regions, respectively. A concentration gradient allows the study of various alloys with different concentration and volume-fraction in a single sample. © 2017, The Korean Institute of Metals and Materials and Springer Science%2bBusiness Media Dordrecht.

publication date

  • 2017-01-01