In Situ SEM Torsion Test of Metallic Glass Microwires Based on Micro Robotic Manipulation

Microwires, such as metallic, semiconductor, and polymer microwires and carbon fibers, have stimulated great interest due totheir importance in various structural and functional applications. Particularly, metallic glass (MG) microwires, because of theiramorphous atoms arrangement, have some unique mechanical properties compared with traditional metals. Despite the fact thatsubstantial research efforts have been made on the mechanical characterizations of metallic glass microwires under tension orflexural bending, the mechanical properties of microwires under torsional loading have not been well studied, mainly due to theexperimental difficulties, such as the detection of torsion angle, quantitative measurement of the torsional load, and the alignmentbetween the specimen and torque meter. In this work, we implemented the in situ SEM torsion tests of individual La50Al30Ni20metallic glass (MG) microwires successfully based on a self-developed micro robotic mechanical testing system. Unprecedenteddetails, such as the revolving vein-pattern along the torsion direction on MG microwires fracture surface, were revealed. Ourplatform could provide critical insights into understanding the deformation mechanisms of other microwires under torsionalloading and can even be further used for robotic micromanufacturing.