| Abstract |
| The mystery of Goss selective abnormal grain growth (AGG) in Fe-3%Si steel has long remained unsolved since its discovery by Goss in 1933. Similarly, the mechanism of secondary recrystallization, which is commonly observed in many metallic systems, has long been a puzzle. Here, attempts to solve this puzzle are reviewed with a focus on solid-state wetting along the triple junction of polycrystalline metals. Especially, the grains with sub-boundaries of very low energy exclusively have a high probability to grow by solid-state wetting and as a result can grow abnormally. The 3-dimensional Monte Carlo (MC) and phase field model (PFM) computer simulations showed that the presence of sub-boundaries induces AGG. The existence of sub-boundaries exclusively in abnormally-growing grains was experimentally confirmed in Fe-3%Si steel and in 5052 Al alloy. The time evolution of abnormally growing grains by ex-situ observation and electron backscattered diffraction (EBSD) analysis of 5052 Al alloy clearly revealed many microstructural evidences for AGG by triple-junction wetting. Misorientation angle measurements by EBSD of the grains belonging to the penetrating morphology showed that the penetrated grain boundaries have high energy and the penetrating grain boundaries tend to have low energy, in agreement with the wetting condition along the triple junction. Parallel three-dimensional MC simulations starting with the experimental misorientationdata, which consider sub-boundaries and precipitates, show many realistic AGG features observed experimentally. (Received July 28, 2013) |
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| Key Words |
| abnormal grain growth, Fe-3%Si steel, 5052 Al alloy, goss grain, secondary recrystallization, solid-state wetting |
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