Magnetic and Invar properties of Fe-35 %Ni alloy after grinding of structure by hydroextrusion

Abstract

The impact of deformation of Invar Fe-35 % Ni alloy by hydroextrusion at room temperature on structure and its properties was studied. Grinding of grains, the structure fragmentation on 60 nm blocks and continuous increasing microstresses with growing e within the strain range of ε = 0.45—3.47 was shown. The multiple extrusion leads to a non-monotonic change of magnetic properties of the alloy (specific magnetization and the Curie temperature) and as a consequence to thermal expansion measured along the direction of the extrusion due to the microstresses growth and their partial relaxation. The hypothesis concerning the microstresses induced change of a balance between ferromagnetic and antiferromagnetic contributions to exchange interspin interaction is supposed.