Production of Glassy Coil Springs by Warm Coiling of Zr-based Glassy Alloy Wires

Abstract

This study examines forming of coil springs from glassy alloy wires by warm coiling. Glassy Zr-Al-Ni-Cu alloy wires with a diameter of 1 mm were prepared by the rotating grooved-disk casting method and were wound round metal molds which were heated up to the supercooled liquid region of the alloy. Coil springs with mean diameters of 19 mm and 7.2 mm were formed by the warm coiling process. The coil springs formed within 1.8 ks in a temperature range between 673 K and 723 K maintained the glassy state, while the part heated for longer time in the coil spring formed at temperatures between 693 K and 743 K was crystallized. The spring constants of the coil springs measured by compressive test agree with the respective spring constant values calculated from the dimensions of the springs and the shear modulus of the alloy.