TY - JOUR
T1 - Crystallization and fracture behavior of the Zr65- xAl7.5Cu17.5Ni10Six bulk amorphous alloys
AU - Jang, J. S.C.
AU - Chen, Y. W.
AU - Chang, L. J.
AU - Cheng, H. Z.
AU - Huang, C. C.
AU - Tsau, C. Y.
N1 - Funding Information:
The authors would like to gratefully acknowledge the sponsorship from the National Science Council of ROC under the project NSC91-2216-E-214-015. The authors are also very grateful for the assistance of TEM studies by Ms. Liang-Chu Wang.
PY - 2005/1/15
Y1 - 2005/1/15
N2 - The crystallization behavior of amorphous Zr65- xAl7.5Cu17.5Ni10Six alloys, x=0-10, was studied by means of differential scanning calorimetry, X-ray diffractometry, and TEM. The calculated Trg (T g/T1) for these amorphous alloys increases with increasing silicon content from 0.55 to 0.60, which indicates that the silicon addition, could improve the GFA for the Zr65-xAl 7.5Cu17.5Ni10Six alloys. The activation energy of crystallization of the alloy 4Si was about 365 ± 5 kJ mol-1, both determined by the Kissinger and Avrami plot. This value is about 20% higher than the base alloy (314 kJ mol-), which implies that the silicon addition can increase the thermal stability for the Zr-based alloy. The average value of the Avrami exponent n were calculated to be 1.7-2.5 for the alloys in this study. In addition, the cube of crystal size as a function of isothermal annealing time presents a linear relationship for the Zr61Al7.5Cu17.5Ni10Si 4 alloy During isothermal annealing the Zr61Al 7.5Cu17.5Ni10Si4 alloy at 698 K, the Zr2Cu crystal with average size of 105 nm was first observed at the early stage (30% crystallization ratio) of crystallization. In addition, both nano-crystals of the ZrCu (∼100nm) and the Zr3Al (∼30nm) were also observed to precipitate from the amorphous matrix upon the middle stage (50% crystallization ratio) of crystallization. The fracture surface presents typical ductile vein pattern for 4Si amorphous alloy ribbon after bended to 180°. However, a ductile-brittle transition phenomenon occurs at the amorphous ribbon after 50% crystallization ratio of isothermal annealing at the temperature between Tg and Tx.
AB - The crystallization behavior of amorphous Zr65- xAl7.5Cu17.5Ni10Six alloys, x=0-10, was studied by means of differential scanning calorimetry, X-ray diffractometry, and TEM. The calculated Trg (T g/T1) for these amorphous alloys increases with increasing silicon content from 0.55 to 0.60, which indicates that the silicon addition, could improve the GFA for the Zr65-xAl 7.5Cu17.5Ni10Six alloys. The activation energy of crystallization of the alloy 4Si was about 365 ± 5 kJ mol-1, both determined by the Kissinger and Avrami plot. This value is about 20% higher than the base alloy (314 kJ mol-), which implies that the silicon addition can increase the thermal stability for the Zr-based alloy. The average value of the Avrami exponent n were calculated to be 1.7-2.5 for the alloys in this study. In addition, the cube of crystal size as a function of isothermal annealing time presents a linear relationship for the Zr61Al7.5Cu17.5Ni10Si 4 alloy During isothermal annealing the Zr61Al 7.5Cu17.5Ni10Si4 alloy at 698 K, the Zr2Cu crystal with average size of 105 nm was first observed at the early stage (30% crystallization ratio) of crystallization. In addition, both nano-crystals of the ZrCu (∼100nm) and the Zr3Al (∼30nm) were also observed to precipitate from the amorphous matrix upon the middle stage (50% crystallization ratio) of crystallization. The fracture surface presents typical ductile vein pattern for 4Si amorphous alloy ribbon after bended to 180°. However, a ductile-brittle transition phenomenon occurs at the amorphous ribbon after 50% crystallization ratio of isothermal annealing at the temperature between Tg and Tx.
KW - Bulk amorphous
KW - Crystallization kinetics
KW - Fracture behavior
KW - Glass transition temperature
KW - Zirconium-based alloy
UR - http://www.scopus.com/inward/record.url?scp=7644220709&partnerID=8YFLogxK
U2 - 10.1016/j.matchemphys.2004.08.014
DO - 10.1016/j.matchemphys.2004.08.014
M3 - 期刊論文
AN - SCOPUS:7644220709
SN - 0254-0584
VL - 89
SP - 122
EP - 129
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
IS - 1
ER -