TY - GEN
T1 - Effects of chemical composition on the structural relaxation in ternary Zr-Cu-Al bulk glassy alloys studied by EXAFS and positron annihilation techniques
AU - Ishii, A.
AU - Mineno, S.
AU - Iwase, A.
AU - Yokoyama, Y.
AU - Konno, T. J.
AU - Hori, F.
N1 - Funding Information:
This work was supported by Grant-in-Aid for JSPS Fellows (22-9161). Authors would like to express cordial thanks to Prof. Haruyama to useful discussions for free volume theory and heat treatment, and to Dr. Okamoto for the EXAFS measurement. This work was also performed under the inter-university cooperative research program of the Advanced Research Center of Metallic Glasses, Institute for Materials Research, Tohoku University.
PY - 2011
Y1 - 2011
N2 - Mechanical properties and thermal stability of bulk glassy alloys depend on their chemical composition ratios, although their detailed local structures especially around free volume have not been clarified yet. In order to know the origin of property dependence on alloy composition in Zr-Cu-Al ternary bulk glassy alloys in a view point of atomic scale, positron annihilation lifetime, coincidence Doppler broadening (CDB) and EXAFS (extended X-ray absorption fine structure) measurements have been employed for eutectic Zr 50Cu 40Al 10 and hypoeutectic Zr 60Cu 30Al 10 bulk glassy alloys before and after structural relaxation by annealing below glass transition temperature T g. The result of CDB experiment, which represents the electron momentum distribution around free volume, shows that significant atomic reordering around free volume does not take place by the annealing in each alloy. Besides, CDB ratio profiles for each alloy suggest that the fraction of Zr atom around free volume does not match the chemical composition of each alloy system. Change in positron lifetime, which is proportional to the size of free volume, during annealing for hypoeutectic alloy almost remains unchanged.
AB - Mechanical properties and thermal stability of bulk glassy alloys depend on their chemical composition ratios, although their detailed local structures especially around free volume have not been clarified yet. In order to know the origin of property dependence on alloy composition in Zr-Cu-Al ternary bulk glassy alloys in a view point of atomic scale, positron annihilation lifetime, coincidence Doppler broadening (CDB) and EXAFS (extended X-ray absorption fine structure) measurements have been employed for eutectic Zr 50Cu 40Al 10 and hypoeutectic Zr 60Cu 30Al 10 bulk glassy alloys before and after structural relaxation by annealing below glass transition temperature T g. The result of CDB experiment, which represents the electron momentum distribution around free volume, shows that significant atomic reordering around free volume does not take place by the annealing in each alloy. Besides, CDB ratio profiles for each alloy suggest that the fraction of Zr atom around free volume does not match the chemical composition of each alloy system. Change in positron lifetime, which is proportional to the size of free volume, during annealing for hypoeutectic alloy almost remains unchanged.
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U2 - 10.1557/opl.2011.468
DO - 10.1557/opl.2011.468
M3 - Conference contribution
AN - SCOPUS:84859082165
SN - 9781618395108
T3 - Materials Research Society Symposium Proceedings
SP - 84
EP - 89
BT - Bulk Metallic Glasses and their Applications
T2 - 2010 MRS Fall Meeting
Y2 - 29 November 2010 through 3 December 2010
ER -