Crystallization in additive manufacturing of metallic glasses: A review

Arising from their unique amorphous microstructure, the excellent physical and functional properties of metallic glasses (MGs) make them promising candidates for many key industrial sectors. With the recent popularity of the additive manufacturing (AM) technique, the design and fabrication of geometrically complex MGs with large practical dimensions have been achieved. It is believed that this will further unlock the potential for the implementation of MGs in various industries. From a scientific and technical perspective, the manipulation or suppression of crystallization of MGs during AM has become one of the main focuses in the field. This review aims to present a systematic overview of the recent research and development regarding one of the emerging and intriguing topics in the AM field. First, the current research status and recent advances in AM fabrication and the crystallization phenomenon for several MG systems are reviewed and discussed. Then, different crystallization mechanisms in different regions in AM-fabricated MGs along with key theories and simulations of crystallization during AM processes are summarized. Following this, challenges and unresolved issues are identified. Finally, concluding remarks and the outlook for future applications and research directions for AM of MGs are provided.