TY - JOUR
T1 - Free volume change in crystallization process of Zr-Cu-Al metallic glass studied by positron annihilation techniques
AU - Hori, Fuminobu
AU - Yano, Takaaki
AU - Yokoyama, Yoshihiko
AU - Akeno, Yasutake
AU - Konno, Toyohiko J.
N1 - Funding Information:
This study has been supported by a Grant-in-Aid for Scientific Research by the Ministry of Education, Culture, Sports, Science and Technology of Japan (Grant number 15074218).
PY - 2007/5/31
Y1 - 2007/5/31
N2 - Positron annihilation lifetime (PAL) and coincidence Doppler broadening (CDB) experiments have been performed to study free volume changes and atomic relaxation behavior in Zr-Cu-Al bulk metallic glass. Zr50Cu40Al10 metallic glass was annealed isothermally at 673 K, which is below the glass transition temperature (Tg). During this annealing, PAL was observed to decrease, indicating a decrease in free volume; whereas, no significant change in CDB spectra was detected. This observation implies that the relaxation below Tg takes place without a change in atomic configuration. As for specimens annealed at 723 K (>Tg) for 100 s and subsequently annealed isothermally at 673 K for 18,000 s, PAL decreased similarly, suggesting a decrease in free volume. In addition, CDB spectra showed a systematic fluctuation of electron momentum distribution, especially in a high momentum region. This indicates that a chemical reordering took place during crystallization process.
AB - Positron annihilation lifetime (PAL) and coincidence Doppler broadening (CDB) experiments have been performed to study free volume changes and atomic relaxation behavior in Zr-Cu-Al bulk metallic glass. Zr50Cu40Al10 metallic glass was annealed isothermally at 673 K, which is below the glass transition temperature (Tg). During this annealing, PAL was observed to decrease, indicating a decrease in free volume; whereas, no significant change in CDB spectra was detected. This observation implies that the relaxation below Tg takes place without a change in atomic configuration. As for specimens annealed at 723 K (>Tg) for 100 s and subsequently annealed isothermally at 673 K for 18,000 s, PAL decreased similarly, suggesting a decrease in free volume. In addition, CDB spectra showed a systematic fluctuation of electron momentum distribution, especially in a high momentum region. This indicates that a chemical reordering took place during crystallization process.
KW - Amorphous materials
KW - Electronic states
KW - Positron spectroscopies
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U2 - 10.1016/j.jallcom.2006.08.143
DO - 10.1016/j.jallcom.2006.08.143
M3 - Article
AN - SCOPUS:33947580605
SN - 0925-8388
VL - 434-435
SP - 207
EP - 210
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - SPEC. ISS.
ER -