| Autor: |
Torizuka, Shiro, Ohmori, Akio, Murty, S.V.S. Narayana, Nagai, Kotobu |
| Zdroj: |
Materials Science Forum; January 2006, Vol. 503 Issue: 1 p329-334, 6p |
| Abstrakt: |
Ultrafine-grained structures formed dynamically through simple compression at warm deformation temperatures were investigated in a 0.15%C- 0.4%Si-1.5%Mn steel. The effects of strain, strain rate and deformation temperature on the microstructural evolution were examined using an isothermal plane strain compression technique with a pair of anvils. The maximum strain was 4, the deformation temperature was below the AC1 temperature, and the Zener-Hollomon parameter (Z) ranged between 1012 s-1 and 1016 s-1. Ultrafine ferrite grains surrounded by high angle boundaries are generated by simple compression when the strain exceeded a critical value. The number of newly generated ultrafine grains increased with the strain; however, the average sizes were found to be independent of strain. The grain size, `d`, was found to depend on Z parameter. An equation, d (μm) =102.07Z-0.16, was found to satisfy the experimentally obtained data. This study demonstrates the possibility of obtaining ultrafine ferrite through multi-pass caliber rolling as a high Z- large strain deformation technique for producing bulk engineering components. It was also noted that the empirical relation established based on single pass compression tests is valid for multi-pass caliber rolling. |
| Databáze: |
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