Estimation of hardness in isothermal aged Fe-Cu alloys with high dislocation density using magnetic hysteresis and thermoelectric power measurements

Abstract

　Magnetic hysteresis loop (MHL) and thermoelectric power (TEP) measurements were performed in isothermal aged Fe-1.0wt.%Cu alloys with different cold-rolling ratio. Coercivity decreased and TEP increased with increasing aging time. Isothermal ageing causes recovery of dislocation microstructures and formation of Cu precipitates. Based on the different relationship between micro-structures and two physical parameters (coercivity and TEP), a simple model for estimating the hardness of Fe-Cu alloys was developed. This study demonstrates the feasibility of the combined electromagnetic techniques for non-destructive evaluation of copper-precipitation hardening in steels with high dislocation density.