Deformation characteristics of ultrafine grained and nanocrystalline iron and pearlitic steel - An in situ synchrotron investigation
| Autor: | Reinhard Pippan, K.S. Kormout, Pradipta Ghosh, U. Lienert, Jozef Keckes |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Yield (engineering) Materials science Polymers and Plastics Cementite Metals and Alloys 02 engineering and technology Strain hardening exponent 021001 nanoscience & nanotechnology 01 natural sciences Electronic Optical and Magnetic Materials chemistry.chemical_compound chemistry Ferrite (iron) 0103 physical sciences Ceramics and Composites Hardening (metallurgy) Lamellar structure Dislocation Pearlite Composite material 0210 nano-technology |
| Zdroj: | Acta Materialia. 160:22-33 |
| ISSN: | 1359-6454 |
| DOI: | 10.1016/j.actamat.2018.08.036 |
| Popis: | The deformation characteristics of ultrafine grained (UFG) iron, ultrafine lamellar (UFL) pearlite and nanolamellar (NL) pearlite were investigated using in situ synchrotron compression tests. The direct measurement of the peak position and peak width of the transmitted diffraction rings provided insights into the correlation between the strain hardening and the evolution of coherent domain size and dislocation density. The results showed that the hard cementite supported the initial hardening in UFL pearlite, while the dislocation density in the ferrite lamellae gradually increased. At higher stresses, the cementite lamellae deformed plastically or fractured, thus transferring the hardening process to the ferrite lamellae. On the other hand, in UFG iron and NL pearlite an initial high strain hardening was observed due to strain path change and redistribution of dislocations. The nanolamellar structure of pearlite further introduced a strong anisotropy in yield behavior, without affecting the hardening characteristics of ferrite lamellae. The physical origin of the anisotropy in flow behavior of NL pearlite was identified as the importance of shear stress on dislocation motion within the ferrite nanolamellae. |
| Databáze: | OpenAIRE |
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