Numerical simulation of Zener pinning with growing second-phase particles
- Los Alamos National Lab., NM (United States). Theoretical Div.
- Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering
The Zener pinning effect with growing second-phase particles in Al{sub 2}O{sub 3}-ZrO{sub 2} composite systems were studied by two-dimensional (2-D) computer simulations using a diffuse-interface field model. In these systems, all second-phase particles are distributed at grain corners and boundaries. The second-phase particles grow continuously, and the motion of grain boundaries of the matrix phase is pinned by the second-phase particles which coarsen through the Ostwald ripening mechanism, i.e., long-range diffusion. It is shown that both matrix grains and second-phase particles grow following the power-growth law, R{sub t}{sup m} {minus} R{sub o}{sup m} = kt with m = 3. It is found that the mean size of the matrix phase (D) depends linearly on the mean size of the second-phase particles (r) for all volume fractions of second phase from 10% to 40%, which agrees well with experimental results. It is shown that D/r is proportional to the volume fraction of the second phase (f) as f{sup {minus}1/2} for a volume fraction less than 30%, which agrees with Hillert and Srolovitz`s predictions for 2-D systems, while experimental results from 2-D cross sections of three-dimensional (3-D) Al{sub 2}O{sub 3}-rich systems showed that either a f{sup {minus}1/2} or a f{sup {minus}1/3} relation might be possible. It is also found that D/r is not proportional to f{sup {minus}1/3} and f{sup {minus}1} in 2-D simulations, which suggests that the Zener pinning effect can be very different in 2-D and 3-D systems.
- Sponsoring Organization:
- USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
- OSTI ID:
- 616485
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 3 Vol. 81; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
Similar Records
Computer simulation of grain growth and Ostwald ripening in alumina-zirconia two-phase composites
A Monte Carlo model of Zener pinning which shows f{sup {minus}1} dependence