**5. Summary and outlook**

Thermoplastic forming provides a promising method to fabricate MGs topological structures and components at various scale sizes, which provides alluring prospects in broadening the application of MGs. The chapter reviews some crucial issues such as the thermoplastic formability, processing techniques and potential applications. Some challenges still exist and impede the practical applications: (1) only few amorphous alloys with excellent glass forming ability, anti-oxidation ability and wide supercooled liquid region, and so on can meet the requirement of thermoplastic forming, (2) the current TPF techniques face challenges in fabricating complicated 3-D structures, (3) the material flow is seriously affected by the interfacial effect on the micro- and nano-scale and the root physical mechanism remains vaguely understood and needs to be settled, and (4) large-scale manufacture is necessary to improve productivity and reduce the cost, if the market of commercial application is developed. Therefore, developing a novel forming technique becomes urgently necessary to breakthrough the alloy systems' limitations. Recent literatures [27–29] have revealed that additive manufacturing (3D printing) is a promising technique for the production of bulk metallic glass (BMG) components without size and alloy system limitations. The authors believe micro-3D printing would provide new opportunities for the creation of small, complex and free-form MG components that were previously unachievable, which would open a new window for MGs fabrication.

## **Acknowledgements**

This work was financially supported by the National Nature Science Foundation of China under Grant nos. 51671090. The authors are also grateful to the Analytical and Testing Center, Huazhong University of Science and Technology for technical assistance.
