The mismatch entropy for bulk metallic glasses: A thermodynamic approach

详细信息    查看全文

• 作者：Xuelian Li ; Kaikai Song ; Yuqin Wu ; Hong Ji ; Li Wang
• 关键词：Amorphous materials ; Glass-forming ability ; Thermodynamic fragility ; Bulk metallic glasses
• 刊名：Materials Letters
• 出版年：2013
• 出版时间：15 September, 2013
• 年：2013
• 卷：107
• 期：Complete
• 页码：17-19
• 全文大小：501 K

文摘

Based on the thermodynamic fragility model, a new parameter (S_¦Ò/k_B)/M is proposed to evaluate the glass-forming ability (GFA) of metallic glasses, where M and S_¦Ò/k_B are the fragility of the superheated melts and the mismatch entropy normalized by the Boltzmann constant, respectively. A positive relationship between (S_¦Ò/k_B)/M and glass forming ability is observed for both bulk metallic glasses and marginal metallic glasses, and an eutectic alloy with (S_¦Ò/k_B)/M larger than 0.17 can be selected as a bulk glassy forming candidate. As most alloys can obtain the temperature dependence of viscosity above liquidus temperature, (S_¦Ò/k_B)/M can be used as a prediction parameter for high GFA. Although both high and low M values can work in determining GFA, the high GFA of bulk metallic glasses is primarily due to the large mismatch entropy (S_¦Ò/k_B>0.17).