Influence of beryllium on thermal stability and glass-forming ability of Zr–Al–Ni–Cu bulk amorphous alloys

Autor: Fang Shoushi, Dong Yuan-Da, Wang Guo-ming, Xueshan Xiao, Hua Qin
Rok vydání: 2004
Předmět:
Zdroj: Journal of Alloys and Compounds. 376:145-148
ISSN: 0925-8388
DOI: 10.1016/j.jallcom.2004.01.014
Popis: Thermal stability and glass-forming ability of Zr 65− x Al 10 Ni 10 Cu 15 Be x ( x =0, 3, 6, 9, 12.5, 16) bulk metallic glasses were investigated by differential scanning calorimetry, differential thermal analysis, X-ray diffraction and high-resolution transmission electron microscopy (HRTEM). The results show that the substitution of beryllium for zirconium strongly affects the supercooled liquid region (Δ T x = T x − T g onset ), the reduced supercooled liquid region (Δ T rg =( T x − T g onset )/( T l − T g onset )) and the reduced glass transition temperature ( T rg = T g / T l ). With increasing of x values, the three parameters that were used to indicate the glass forming ability and thermal stability increase first and then decrease. It is in agreement with the result that these glasses gradually change from an off-eutectic composition into a eutectic one ( x =12.5) that favours higher glass-forming ability, and then there is again a departure from the eutectic composition. Consequently, a moderate Be content will favor to increase the glass forming ability and thermal stability in Zr 65− x Al 10 Ni 10 Cu 15 Be x bulk amorphous alloys. The effect of Be was explained in terms of Miedema’s theory, electronegativity difference and atomic size parameter of the amorphous alloys.
Databáze: OpenAIRE
Externí odkaz: