Deformation behavior of magnesium in the grain size spectrum from nano- to micrometer

作者：Choi H J; Kim Y; Shin J H; Bae D H^*

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2010, 527(6): 1565-1570.

DOI：10.1016/j.msea.2009.10.035

• Nanocrystalline metals
• Deformation behavior
• Magnesium
• Twin
• Grain boundary sliding

This study investigates the deformation behavior of magnesium produced by hot extrusion of ball-milled powders in grains ranging from 120 mu m down to 60 nm in size. For microcrystalline magnesium, lattice dislocation interactions with grain boundaries and/or twin boundaries provide a Hall-Petch relationship between the flow stress and the grain size. The Hall-Petch slope is negatively deviated as the grain size is reduced below 1 mu m since twinning offers an additional deformation mode. As the grain size is further reduced below 100 nm, twinning is significantly suppressed and a portion of grain boundary sliding for plastic deformation increases, providing an inverse Hall-Petch relationship. Microstructure observation, a negligible strain hardening rate, a relatively high index of strain rate sensitivity. and a low activation volume in compression tests also demonstrate the particular deformation behavior of nanocrystalline magnesium.

• 出版日期2010-3-15