Anisotropy of the Thermal Expansion of a Polycrystalline Ni–Mn–Ga Alloy Subjected to Plastic Deformation by Forging

• Published in: Physics of the solid state Vol. 60; no. 6; pp. 1061 - 1067
• Main Authors: Musabirov, I. I., Safarov, I. M., Galeyev, R. M., Gaisin, R. A., Koledov, V. V., Mulyukov, R. R.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.06.2018; Springer; Springer Nature B.V
• Subjects: Analysis; ANISOTROPY; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTALLOGRAPHY; DISTRIBUTION; Forging; GALLIUM COMPOUNDS; GRAIN SIZE; Grain size distribution; HEUSLER ALLOYS; Magnetic alloys; Manganese; MANGANESE COMPOUNDS; Martensitic transformations; Metals; Metals (Materials); Microstructure; Nickel base alloys; NICKEL COMPOUNDS; PHASE TRANSFORMATIONS; Phase transitions; Physics; Physics and Astronomy; Plastic deformation; PLASTICITY; POLYCRYSTALS; Solid State Physics; Specialty metals industry; STABILITY; TERNARY ALLOY SYSTEMS; TEXTURE; THERMAL EXPANSION; Thermomechanical treatment; THERMOMECHANICAL TREATMENTS
• ISSN: 1063-7834; 1090-6460
• DOI: 10.1134/S1063783418060240

The formation of a sharp crystallographic texture in a Ni–Mn–Ga Heusler alloy by the multiple isothermal forging has been studied. An analysis of the thermal expansion near the martensitic transformation temperatures in the as-cast and forged states of the alloy shows that the thermomechanical treatment leads to an increase in the anisotropy of the sample geometric size changing during the phase transformation, which favors an increase in the functional characteristics of the alloy. The structural studies show that the alloy structure after multiple isothermal forging has the bimodal distribution of grain sizes. The formation of the bimodal structure by forging is assumed to make it possible to enhance the stability of the functional properties of the alloy during repeated cycles of the phase transformation.