High-Temperature Deformation Processing Map Approach for Obtaining the Desired Microstructure in a Multi-component (Ni-Ti-Cu-Fe) Alloy

An equiatomic NiTiCuFe multi-component alloy with simple body-centered cubic (bcc) and face-centered cubic solid-solution phases in the microstructure was processed by vacuum induction melting furnace under dynamic Ar atmosphere. High-temperature uniaxial compression experiments were conducted on it in the temperature range of 1073 K to 1303 K (800 °C to 1030 °C) and strain rate range of 10⁻³ to 10⁻¹ s⁻¹. The data generated were analyzed with the aid of the dynamic materials model through which power dissipation efficiency and instability maps were generated so as to identify the governing deformation mechanisms that are operative in different temperature–strain rate regimes with the aid of complementary microstructural analysis of the deformed specimens. Results indicate that the stable domain for the high temperature deformation of the multi-component alloy occurs in the temperature range of 1173 K to 1303 K (900 °C to 1030 °C) and \( \dot{\varepsilon } \) range of 10⁻³ to 10^−1.2 s⁻¹, and the deformation is unstable at T = 1073 K to 1153 K (800 °C to 880 °C) and \( \dot{\varepsilon } \) = 10⁻³ to 10^−1.4 s⁻¹ as well as T = 1223 K to 1293 K (950 °C to 1020 °C) and \( \dot{\varepsilon } \) = 10^−1.4 to 10⁻¹ s⁻¹, with adiabatic shear banding, localized plastic flow, or cracking being the unstable mechanisms. A constitutive equation that describes the flow stress of NiTiCuFe multi-component alloy as a function of strain rate and deformation temperature was also determined.