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

Autor: J.L. Hernández-Rivera, C. G. Garay-Reyes, R. Martínez-Sánchez, E.J. Gutiérrez-Castañeda, S. E. Hernández-Martínez, J.J. Cruz-Rivera, Hector J. Dorantes-Rosales, Joaquin Aguilar-Santillan
Rok vydání: 2017
Předmět:
Zdroj: Metals and Materials International. 23:298-307
ISSN: 2005-4149
1598-9623
DOI: 10.1007/s12540-017-6388-3
Popis: 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%)/Ni generated by diffusion couple. The coarsening of precipitates was evaluated in two different Ti contents (R1-11.4Ti (at%) and R2-13Ti (at%)) 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%) and 9.92Ti (at%) 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 (Q i ) and LSW (Q r ) are Q r : 219.69 and 172.61 kJ mol-1 for R1 and R2 regions, respectively, and Q i : 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.
Databáze: OpenAIRE
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