ISSN:
1551-2916
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The Zener pinning effect with growing second-phase particles in Al2O3-ZrO2 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, Rtm - R0m = 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−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) Al2O3-rich systems showed that either a f−1/2 or a f−1/3 relation might be possible. It is also found that D/r is not proportional to f−1/3 and f−1 in 2-D simulations, which suggests that the Zener pinning effect can be very different in 2-D and 3-D systems.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1151-2916.1998.tb02370.x
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