Zr60Al7.5Ni10Cu17.5Si4B1非晶質合金之結晶行爲及熱穩定性之探討

Study of the Crystallization and Thermal Stability of the Zr60Al7.5Cu17.5Ni10Si4B1 Amorphous Alloy

鄭憲清(J. S. C. Jang) ； 王怡華(I. H. Wang) ； 張量然(L. J. Chang) ； 張均富(C. F. Chang) ； 黃宥祺(Y. C. Huang) ； 蕭証文(T. W. Shau)

《材料科學與工程》 38卷3期 (2006/09) Pp. 169-174

https://doi.org/10.6409/JMSE.200609.0169

摘要

Zr60Al7.5Cu17.5Ni10Si4B1合金利用示差掃描熱分析(DSC)、X光繞射分析儀(X-ray)及穿透式電子顯微鏡(TEM)探討該合金之微觀組織及結晶行爲。Zr60Al7.5Ni10Cu17.5Si4B1合金在JMA方程式中，Avrami指數n值介於1.8~2.5之間，其成核速率呈現遞減現象。在XRD及TEM之微結構分析觀察可知，在714K，恆溫退火熱處理後之試片，在低溫及結晶初期其合金內的結晶相爲Zr2Cu，將恆溫退火熱處理之晶粒大小計算後可發現，Zr2Cu晶粒大小在三次方時與退火時間呈線性關係。並計算其結晶成長動力學發現其成長活化能約爲210±25kJ/mole，相似於Zr65Cu27.5Al7.5合金(165kJ/mole)，但遠小於Zr65Cu35合金(440kJ/mole)，在Inoue等人研究指出，結晶成長活化能很低是因爲結晶成長時，合金內部的擴散是利用小原子，如Si或Al，而通常結晶成長活化能很大，則是因爲在非晶質合金中的擴散是利用大原子，如Zr。

關鍵字

非晶質合金 ； 微結構 ； 結晶成長動力學 ； 示差掃描熱分析儀DSC

並列摘要

The crystallization behavior and microstructure development of Zr60Al7.5Cu17.5Ni10Si4B1 amorphous alloy during isothermal annealing were examined by means of the isothermal DSC, X-ray diffractometry and TEM techniques. According to the calculation by JMA equation, the value of Avrami exponent n exhibits insensitive with annealing temperature being around 1.8 to 2.5 at temperature of 709 K to 724 K, respectively. This indicates that a decreasing nucleation rate of crystallization for the Zr60Al7.5Cu17.5Ni10Si4B1 alloy at supercooled temperature region. When isothermal annealing the Zr60Al7.5Cu17.5Ni10Si4B1 alloy at 714K, nano-sized Zr2Cu crystals were first observed at the early stage of 1% crystallization by TEM observation. In addition, the grain growth time as a function of the cube of particle size of the Zr2Cu type crystalline phases presented a good linear relationship. This indicates that the crystal growth of the Zr60Al7.5Cu17.5Ni10Si4B1 alloy belongs to thermal activation process. The activation energy for the grain growth of Zr2Cu in the Zr60Al7.5Cu17.5Ni10Si4B1 amorphous alloy is calculated to be 210±25 kJ/mole. The lower activation energy of grain growth of crystallization in comparison with 440 kJ/mole for Zr65Cu35 crystal corresponds to the rearrangement of other smaller atoms in the glass, such as Al or Si (compare to Zr).

並列關鍵字

Crystallization ； thermal stability ； amorphous alloy ； zirconium-based alloy ； grain growth Thanks a lot