Absolute concentration of free volume-type defects in ultrafine-grained Fe prepared by high-pressure torsion

作者：Oberdorfer Bernd; Lorenzoni Bernd; Unger Katrin; Sprengel Wolfgang; Zehetbauer Michael; Pippan Reinhard; Wuerschum Roland

来源：Scripta Materialia, 2010, 63(4): 452-455.

DOI：10.1016/j.scriptamat.2010.05.007

• High-pressure torsion
• Nanocrystalline iron
• Crystal defects
• Recrystallization

A maximum excess volume Delta V/V approximate to 1.9 x 10(-3) in ultrafine-grained Fe prepared by high-pressure torsion is determined by measurements of the irreversible length change upon annealing employing a high-resolution differential dilatometer. Since dislocations and equilibrium-type grain boundaries cannot fully account for the observed released excess volume, the present study yields evidence for a high concentration of free volume-type defects inherent to nanophase materials, which is considered to be the main source of their particular properties, such as strongly enhanced diffusivities.

• 出版日期2010-8