Effect of aging and plastic deformation on the mechanical, magnetic, and thermal properties of cobalt-containing invars

The mechanical, magnetic, and thermal properties of water-quenched (from 1150DGC) alloys, such as H36K10T3, H36K10X5T2, and H36K5T2, which were strengthened by aging (at 650DGC) and high-temperature deformation (1100-800DGC) followed by aging, are studied. The decomposition of a supersaturated solid solution in the Invar alloys under study was shown to increase the strength properties and coercive force but to decrease the plasticity and saturation magnetization. In this case, the aging ambiguously affects thermal expansion coefficient a of the different alloys; the temperature range of invariance decreases. The plastic deformation of Invars was found to increase the ultimate strength, yield strength, and coercive force. The additional aging of deformed materials increases the strength and decreases the plastic properties; among the magnetic parameters, the saturation magnetization exhibits the most adequate correlation with the mechanical properties. The thermal properties (the alpha coefficient and invariance range) resulting from the complex heat treatment differ slightly from those resulting from the single aging.