کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1579749 | 1001230 | 2010 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Deformation behavior of magnesium in the grain size spectrum from nano- to micrometer Deformation behavior of magnesium in the grain size spectrum from nano- to micrometer](/preview/png/1579749.png)
This study investigates the deformation behavior of magnesium produced by hot extrusion of ball-milled powders in grains ranging from 120 μm 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 μm 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.
Journal: Materials Science and Engineering: A - Volume 527, Issue 6, 15 March 2010, Pages 1565–1570