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Precipitate Coarsening by Liquid Film Migration in (Mg,Ca)‐PSZ's
Author(s) -
Dickerson Robert M.,
Laraia Vincent J.,
Heuer Arthur H.
Publication year - 1994
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1994.tb04658.x
Subject(s) - materials science , grain boundary , isothermal process , phase (matter) , precipitation , tetragonal crystal system , grain growth , crystallography , chemical engineering , microstructure , thermodynamics , metallurgy , chemistry , crystal structure , physics , organic chemistry , meteorology , engineering
Precipitate coarsening involving preferential growth of solute‐poor tetragonal ZrO 2 precipitates along grain boundaries, combined with migration of grain boundaries containing a liquid silicate phase to form solute‐rich precipitate‐free cubic ZrO 2 , has been observed in grain boundary regions of MgO–CaO–ZrO 2 and CaO–ZrO 2 alloys during isothermal aging at 1400°C. Studies of alloys with 9.5 mol% total solute, but with varying MgO/CaO ratios, demonstrated a marked composition dependence of the phase separation process, in that such phase separation was rare in MgO‐rich materials. The migration process is analyzed using models developed for migration in less complex materials, and a mechanism incorporating orientation‐dependent precipitate strain energies is proposed.