TY - JOUR
T1 - Effect of thermal annealing on the local structure in ZrCuAl bulk metallic glass
AU - Ishii, Akito
AU - Iwase, Akihiro
AU - Fukumoto, Yuka
AU - Yokoyama, Yoshihiko
AU - Konno, Toyohiko J.
AU - Hori, Fuminobu
N1 - Funding Information:
Authors would like to express cordial thanks to Prof. Haruyama to useful discussions for free volume theory and heat treatment. This work was financially supported by Sasakawa Scientific Research Grant from The Japan Science Society. 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. Authors would also like to express cordial thanks to Dr. Y. Okamoto to useful discussions for EXAFS analysis.
PY - 2010/8
Y1 - 2010/8
N2 - The relaxation and crystallization behaviors of the ternary Zr 50Cu40Al10 bulk metallic glass were investigated by the positron annihilation measurements and the extended X-ray absorption fine structure (EXAFS) analysis at the Zr K-edge. The result of positron annihilation coincidence Doppler broadening (CDB) for as-prepared specimen suggests that the fraction of Zr atom around free volume is greater than that of composition for alloy system. According to the results of CDB spectrum and Fourier transformed EXAFS spectrum, the isothermal annealing below the glass transition temperature (Tg) (structural relaxation) decreases the size of free volume, but it causes little change in the distribution of atoms, either around free volume or around Zr atoms. For the isothermal annealing above crystallization temperature (Tx), the XRD and EXAFS spectra clearly show the crystallization of specimens. The CDB result also suggests the crystallization. These results demonstrate that the chemical order around free volume is dissociated, and crystallized order is newly formed during the thermal annealing above Tx.
AB - The relaxation and crystallization behaviors of the ternary Zr 50Cu40Al10 bulk metallic glass were investigated by the positron annihilation measurements and the extended X-ray absorption fine structure (EXAFS) analysis at the Zr K-edge. The result of positron annihilation coincidence Doppler broadening (CDB) for as-prepared specimen suggests that the fraction of Zr atom around free volume is greater than that of composition for alloy system. According to the results of CDB spectrum and Fourier transformed EXAFS spectrum, the isothermal annealing below the glass transition temperature (Tg) (structural relaxation) decreases the size of free volume, but it causes little change in the distribution of atoms, either around free volume or around Zr atoms. For the isothermal annealing above crystallization temperature (Tx), the XRD and EXAFS spectra clearly show the crystallization of specimens. The CDB result also suggests the crystallization. These results demonstrate that the chemical order around free volume is dissociated, and crystallized order is newly formed during the thermal annealing above Tx.
KW - Crystallization
KW - EXAFS
KW - Metallic glass
KW - Positron annihilation spectroscopy
KW - Structural relaxation
KW - Thermal annealing effect
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U2 - 10.1016/j.jallcom.2010.02.072
DO - 10.1016/j.jallcom.2010.02.072
M3 - Article
AN - SCOPUS:77955924831
SN - 0925-8388
VL - 504
SP - S230-S233
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - SUPPL. 1
ER -