Properties of shape memory Fe-based alloys after hydroextrusion treatment

Hydroextrusion treatment at room temperature (''cold'' hydroextrusion) and hydroextrusion at heating (''hot'' hydroextrusion) were used to produce samples of Fe-Ni-Co-Ti shape memory alloys (SMA). The hot hydroextrusion (hydrostatic pressure value, temperature and compression degree are equal to 0.9 GPa, 1073 K and 78%, respectively) of the preliminary hot rolled and subsequently quenched alloy was shown to induce about twice larger level of reversible strain due to the gamma reversible arrow alpha transformation as compared with the initial state. Cold hydroextrusion treatment applied to as-cast quenched Fe-Ni-Co-Ti alloy caused significant deepening of minimum at the M(s) vs aging time dependence. It was experimentally confirmed that homogenization degree in Fe-Ni-Co-Ti alloys is enhanced after the hydroextrusion treatment.