Survey of piezomagnetic properties of Fe-35%Co alloys (% by mass) with addition of 0.5 and 0.7% of Nb

• Grant number: 22/15334-0
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: April 01, 2023
• End date: June 30, 2023
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Cristina Bormio Nunes
• Grantee: Matheus Marinho Arruda
• Supervisor: Olivier Hubert
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil
• Institution abroad: Université Paris-Saclay, France
• Associated to the scholarship: 22/09152-7 - Influence of Nb addition on the magnetic and mechanical properties of Fe-35%Co alloy (mass %), BP.IC

Abstract

In the ongoing project FAPESP 2021/06350-0 , the study of the addition of Cr to improve the mechanical property of the Fe-35%Co binary alloy is followed by the study of the addition of Ti to the Fe-35%Co+Cr alloy. The Ti addition aims to increase the magnetic permeability and decrease the magnetostriction. In this project, the intended use of the material is as core sheets for electrical machines, seeking greater energy efficiency, especially in applications related to electric cars motors and aircraft. In the ongoing Scientific Initiation Project of the candidate Matheus Marinho Arruda, we study the modification of the Fe-35%Co alloy, by adding Nb instead of Cr, but without adding Ti. The alloy with addition of Cr is being studied by another student. The small addition of Nb is intended to compare with the effect of the addition of Cr, whose addition was developed in 1947 to improve the deformability of the Fe-35%Co alloy. Nb is also a stabilizer of the disordered bcc phase, as well as Cr, which would prevent the ordering of the bcc phase and reduce the brittleness of the alloy. It is not expected that the addition of small amounts of Nb will cause a decrease in the magnetostriction of the material, since the amounts of Nb are less than 1%. The saturation magnetostriction of the Fe-35%Co alloy is ~ 80 x 10-6. This value is close to that obtained for polycrystalline Fe-Ga (90 x 10-6), which has excellent magnetomechanical properties. Furthermore, the high values of saturation magnetic induction could also be interesting for these applications. Therefore, the Fe-35%Co alloy with the addition of Nb could be suitable for sensor and actuator applications, and to determine this, the piezomagnetic properties need to be determined. This characterization of the piezomagnetic properties (magnetomechanical behavior) is complementary to the Scientific Initiation work in progress, and the same material produced for the characterization of the magnetic properties and the microstructure will be used for the determination of the piezomagnetic coefficients. This characterization proposed here is relevant, because as shown, the material has high magnetostriction, may have good mechanical workability and will determine whether the material is suitable for use in devices such as sensors or actuators. The objectives of the project are to carry out measurements of:1) Magnetic induction (B) for fixed field (H) and varying applied tension and compression values (Sigma).2) Longitudinal magnetostriction (Lambda) for fixed applied voltage values and varying applied field values (hysteretic and anhysteretic measurements).3) Magnetic induction (B) for fixed values of applied voltage and varying values of applied field H (hysteretic and anhysteretic measurements).4) Longitudinal magnetostriction for fixed field (H) and varying values of applied tension and compression (Sigma). (AU)