Magnetic measurement of strain-induced martensite formation in Fe–30Ni steel

<p>This investigation focuses on deformation-induced plasticity in Invar-type steel alloys. The effect is being studied in an austenitic model alloy, containing 30 wt-% of nickel. Its temperature dependent mechanical properties are being presented. Furthermore, the martensitic phase content has been determined by magnetic means in an alloy with two ferromagnetic phases for the first time. The results show that the α′-martensite formation within the austenitic phase with primarily wavy glide mechanism allows an increase in ductility of around 10% at the <i>M</i>_sσ temperature of −5°C. This is the point of maximum uniform elongation. Near the <i>M</i>_s temperature, a microstructure of 70 vol.-% deformation-induced α′-martensite can be achieved.