Metallic wires, as a distinctive type of structural and functional materials, have a long history and play irreplaceable roles in the fields of energy, transportation, marine vessels and so on. With the development of national strategic demands, the new generation of major equipment faces challenges in extreme service environments, such as deep space, deep sea and polar regions, and the corresponding harsh application scenarios, i.e., high-speed impact, cryogenic temperature and corrosion, etc., pose significant challenges to the service reliability of high-strength metallic wires. Therefore, not only to provide adequate supports for most challenged structural applications, but also to save material cost, developing high-performance metallic wires and revealing their mechanical behavior have been pressing and vital subjects. Up to date, researchers have invented numerous wire preparation technologies, including the drawing method, glass coated method, rotating water melt-spinning method, melt-extraction method and drawing method in the supercooled liquid region, leading to the emergence of various high-performance metallic wires, such as traditional pearlitic steel wires, amorphous alloy wires and high entropy alloy wires, etc. Among high-strength metallic wires, conventional pearlitic steel wires currently hold the world record for the highest tensile strength of metallic wires, while novel high entropy alloy wires have successfully addressed the strength-ductility trade-off dilemma among traditional wires, as well as the issues of low-temperature brittleness, showing great application potential under harsh service circumstances. Due to the different microstructures and physical and chemical properties, different types of metallic wires exhibit unique mechanical behaviors and complex plastic deformation mechanisms. The high strength of polycrystalline alloy wires, e.g., pearlitic steel wires and high entropy alloy wires, primarily arises from multiple strengthening mechanisms, such as boundary hardening, dislocation hardening, precipitation strengthening, etc., while the high strength of amorphous alloy wires stems from their intrinsic atomic disordered structures. The plastic deformation of polycrystalline alloy wires is characterized by a variety of complex plastic deformation mechanisms, including dislocation motion, propagation of stacking faults, deformation twinning, phase transformation and their interactions, while the plastic deformation of amorphous alloy wires is mainly related to the activation and aggregation of flow defects. In order to further enhance the strength and ductility of metallic wires, researchers have proposed amounts of effective methods, such as regulating alloy composition, refining microstructures and designing non-uniform structures. As the diameter of metallic wire decreases, a deformation size effect become apparent, then the strain-gradient plasticity theory that considers this size effect has been developed and effectively applied to describe the mechanical behavior of these m...
