The Effect of the In-Situ Heat Treatment on the Martensitic Transformation and Specific Properties of the Fe-Mn-Si-Cr Shape Memory Alloys Processed by HSHPT Severe Plastic Deformation

Carmela Gurau; Gheorghe Gurau; Felicia Tolea; Bogdan Popescu; Mihaela Banu; Leandru-Gheorghe Bujoreanu

doi:10.3390/ma14164621

The Effect of the In-Situ Heat Treatment on the Martensitic Transformation and Specific Properties of the Fe-Mn-Si-Cr Shape Memory Alloys Processed by HSHPT Severe Plastic Deformation

Materials (Basel). 2021 Aug 17;14(16):4621. doi: 10.3390/ma14164621.

Authors

Carmela Gurau¹, Gheorghe Gurau¹, Felicia Tolea², Bogdan Popescu², Mihaela Banu³, Leandru-Gheorghe Bujoreanu⁴

Affiliations

¹ Faculty of Engineering, "Dunarea de Jos" University of Galati, Domneasca Street 47, 800008 Galati, Romania.
² National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania.
³ Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, MI 48109, USA.
⁴ Faculty of Materials Science and Engineering, The "Gheorghe Asachi" Technical University of Iasi, Blvd. Dimitrie Mangeron 61A, 700050 Iasi, Romania.

Abstract

This work focuses on the temperature evolution of the martensitic phase ε (hexagonal close packed) induced by the severe plastic deformation via High Speed High Pressure Torsion method in Fe₅₇Mn₂₇Si₁₁Cr₅ (at %) alloy. The iron rich alloy crystalline structure, magnetic and transport properties were investigated on samples subjected to room temperature High Speed High Pressure Torsion incorporating 1.86 degree of deformation and also hot-compression. Thermo-resistivity as well as thermomagnetic measurements indicate an antiferromagnetic behavior with the Néel temperature (T_N) around 244 K, directly related to the austenitic γ-phase. The sudden increase of the resistivity on cooling below the Néel temperature can be explained by an increased phonon-electron interaction. In-situ magnetic and electric transport measurements up to 900 K are equivalent to thermal treatments and lead to the appearance of the bcc-ferrite-like type phase, to the detriment of the ε(hcp) martensite and the γ (fcc) austenite phases.

Keywords: Fe-Mn-Si-Cr; HSHPT; ferromagnetic shape memory alloy; magnetic properties; martensitic transformation; severe plastic deformation; transport properties.

Abstract

Grants and funding