Effect of Electromagnetic Stirring Current on the Microstructure, Mechanical and Tribological Properties of Copper/Steel Bimetal

Abstract

Based on the traditional liquid-solid composite casting method, copper/steel bimetallic samples were prepared by electromagnetic stirring (EMS), and the effects of electromagnetic stirring current on the microstructure, mechanical properties and wear property of copper/steel bimetal were studied. The results showed that EMS was benefical for grain refinement. The structure of the α-Cu phase without EMS was all dendrites, as the stirring current increased, the α-Cu phase gradually changed to near-spherical crystals, and the average grain size of copper/steel bimetallic copper layer decreases from 517.6 μm to 54.7 μm. When the stirring current was 300 A, the interdiffusion distance of Cu and Fe atoms reached 9.4 μm, the interfacial shear strength reached to 217 MPa, which was increased by 36.5% compared with that without EMS, the average friction coefficient of the copper layer decreased to 0.216, and the wear rate was reduced to 1.499×10-7 mm3/(N·m), which was reduced by 26.7% compared with that without EMS. Additionally, the wear mechanism changed from delamination wear to slight abrasive wear and adhesive wear.

Keywords: Copper/Steel bimetal, Electromagnetic stirring, Mechanical property, Tribological property