Stabilization of high-temperature shape memory effect in functional Ni–Al–Co martensitic alloys

Abstract

Resistometry and electron microscopy were used to study Ni 65Al 35 and Ni 56Al 34Co 10 (at.%) alloys prepared by the method of accelerated melt spinning. Ribbon samples were studied during and after different heating–cooling cycles or different isothermal holding conditions at temperatures of up to 780 °C. A method was proposed for improvement of the heat resistance of the supersaturated β solid solution and stabilization of the reversibility of the high-temperature martensitic transformation in alloys of the Ni–Al system. This method consists in a partial replacement of nickel by cobalt, accelerated melt spinning, and short-time stabilization annealing in the low-temperature range of the B2 austenite.