Non-Isothermal Crystallization Kinetics of a Rapidly Solidified as-Cast TiZrHfNiCu High Entropy Bulk Metallic Glass

• 作者: Nur Ayuni Jamal
• 来源期刊: 世界工程和技术(英文)
• 学科: 工学
• 关键词: Crystallization Kinetics High Entropy Bulk Metallic Glass Phase Transformation Sluggish Diffusion
• 年，卷（期）: 2020,（3）
• 页码范围: 280-295
• 页数: 16页
• 分类号: TG1

摘要

This paper aims to investigate the thermal behavior and crystallization kinetics of TiZrHfNiCu high entropy bulk metallic glass (HE-BMG) alloy using the standard procedure of Differential Scanning Calorimetric (DSC) annealing technique.</span><b><span style="font-family:Verdana;"> </span></b><span style="font-family:Verdana;">The alloy was produced using an arc melting machine with a critical diameter of 1.5 mm. The crystallization kinetics and phase transformation mechanism of TiZrHfNiCu HE-BMG was investigated under the isochronal condition at a single heating run based on the Johnson-Mehl-</span></span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">Avrami (JMA) theory. In isochronal heating, the apparent activation energy for glass transition and crystallization events w</span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> analyzed by Kissinger and Ozawa methods. The average activation energy value for crystallization of TiZrHfNiCu amorphous alloys in isochronal modes was 226.41 kJ/mol for the first crystallization and 297.72 kJ/mol for second crystallization stages. The crystallization mechanism of the first step was dominated by two</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> and three-dimensional growth with increasing nucleation rate, while the crystallization mechanism in the second stage was dominated by two-dimensional crystallization growth with a constant nucleation rate. The diffusion mechanism result proved the theory of sluggish atomic diffusion of HEA at elevated temperature.