Magnetic and structural properties of hot pressed Cu–SmCo5 composites obtained by mechanical alloying

Abstract

Cu–8 wt-%SmCo5 alloys were obtained through mechanical milling for novel industrial applications. Copper and SmCo5 powder mixtures were mechanically alloyed in a planetary ball mill to disperse SmCo5 fine particles in the copper matrix with the aim to modify the structural, mechanical, electrical and magnetic properties. The resulting alloyed powders were characterised as a function of milling time. Under the magnetic field, SmCo5 particles achieved Ms to improve the soft magnetic properties of copper–8 wt-%SmCo5 to be used in dielectromagnetic components. The magnetic properties of Cu–8 wt-%SmCo5 powders reached their optimum values after milling time ranging from 10 to 15 h. The consolidation of milled alloy powders was performed by uniaxial hot pressing at 923 K for 2 h under argon atmosphere to obtain dense compacts. The consolidation process resulted in good dense metal matrix composite materials with adequate properties of compression strength >900 MPa, 95 HRB in hardness, electrical conductivity up to 43% of that of the International Annealed Copper Standard (IACS) and magnetic properties such as coercive field, saturation and remanent magnetisation obtained at 218 Oe, 70·23 emu g−1 and 6·09 emu g−1 respectively at 300 K. The existence of a coercive field and a little magnetic memory of the consolidated system is a typical behaviour of magnetically soft materials. The variation of electric and magnetic properties and its dependence on structure strength change with milling time were discussed.