Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 35: Poster Session II
MM 35.13: Poster
Mittwoch, 25. März 2009, 16:30–18:30, P4
Quantification of free volume variations of Pd40Ni40P20 bulk metallic glass deformed by room temperature rolling — •yuanli xu1,2, yue zhang1, jixiang fang1, horst hahn1, and jiangong li2 — 1Forschungszentrum Karlsruhe, Institut for Nanotechnology, Karlsruhe 76021, Germany — 2Institute of Materials Science and Engineering, Lanzhou University, Lanzhou 730000, China
Mechanical and thermal properties of metallic glasses change significantly with increasing inhomogeneous deformation. This can be attributed to the introduction of localized excess free volume in shear bands. Therefore, the quantification of free volume is of importance for understanding of the structure of the shear bands and the corresponding changes in mechanical and thermal properties of metallic glasses. In the present work, the Pd40Ni40P20 (at.%) bulk metallic glass prepared by suction casting method was deformed to different strains by rolling at room temperature at a constant strain rate. Differential scanning calorimetry was employed to measure the variation of heat capacity with temperature for the undeformed and rolled Pd40Ni40P20 bulk metallic glass. The average value of the reduced free volume was quantitatively calculated from heat capacity for different strains. Compared with the undeformed Pd40Ni40P20 bulk metallic glass, about 23 % excess free volume was introduced into the rolled Pd40Ni40P20 bulk metallic glass at a strain exceeding 90%. These results may be helpful for understanding of the structure of the shear bands in the bulk metallic glasses and the properties of the deformed bulk metallic glasses.