The preparation of ductile high strength Fe-base filaments using the methods of glass-coated melt spinning

High toughness glass-coated metallic fibres show great promise for use in composite materials as reinforcement for brittle matrixes such as fine ceramics. This paper describes the glass-coated melt spinning of austenitic steel and Fe-B base alloys in order to prepare a ductile high strength filament. The toughness was estimated from the area of the stress-strain curves of the filament obtained. Continuous high toughness steel filament, which had a maximum toughness of 6600 MPa% with a tensile strength of 3050 MPa and an elongation of 3.1% was obtained from the molten state at 1600 K for a winding speed of 7.95 m sec^–1. The filament was 3×10^–6m diameter and polycrystalline with a grain size of 1000×10^–10m. The crystal structure of the filament was a single b c c phase and the phase transformed into a stable f c c structure by heat treatment at 1073 K for 600sec. Ductile filaments of Fe_78-xCo₅Ni₅Cu₂B₁₀M_x (M_xCr_5–20, Cr₅Si₃, Cr₅Co₅, Cr₅Ni₅, Cr₁₀Mo_0.5, Cr₁₀Nb_0.5) alloys were also successfully produced. The Fe_67.5Co₅Cr₁₀Ni₅Cu₂B₁₀Mo_0.5 filament had the highest toughness of 13 900 MPa% with tensile strength of 3760 MPa and an elongation of 4.8%. The filament had a single b c c phase.