Spark Plasma Sintering: A Useful Technique to Develop Large-Sized Bulk Metallic Glasses

Metallic glasses exhibit unique combination of physical, chemical and mechanical properties due to their amorphous nature which lacks long range order and defects such as grain boundaries and dislocations [1,2]. In the past two decades, they have been rapidly developed for application in many fields. However, the disadvantages such as poor plasticity and limited dimensions hamper their large-scale industrial applications [3,4]. The most common method to improve plasticity of the monolithic bulk metallic glasses (BMGs) is to produce glassy composites by introducing nanoor micro-scale crystalline phases into the metallic glassy matrix [5-9]. On the other hand, intensive efforts have been made to overcome dimension limitation. Powder metallurgy process is an alternative route to produce large-size metallic glassy alloy parts. It is also favor to fabricate the glassy composites by dispersing crystalline particulates into the glassy matrix. Spark plasma sintering (SPS) as a newly developed rapid sintering technique, has a great potential for producing glassy composites while crystallization of the glassy alloy and coarsening of the dispersed particles are avoided. Furthermore, it is also a type of solid-state compression sintering technique which is similar to hot pressing sintering process, so that the sintered samples with the large-size and complicated shape can be produced [10,11].