A magnetically soft yet mechanically strong and ductile Ta free CoFeNi high entropy alloy with Al and Ti additions
Journal article, 2026
Next generation high speed, large torque, rotating electrical machines demand materials with an excellent balance of magnetic and mechanical properties. High entropy alloys (HEAs) can exhibit this unique combination of properties, e.g., CoFeNi based HEAs containing Ta. The high Ta content makes these alloys prohibitively expensive for industrial applications. Hence, we develop Ta free HEA using a thermodynamic approach. The addition of Al and Ti to the base CoFeNi alloy is studied. We investigate two compositions: Ti0.24CoFeNi0.78 and Al0.3Ti0.2CoFeNi. In their solution treated and quenched condition these HEAs exhibit a low coercivity H-c similar to 1.8-2.4 Oe, high saturation magnetization M-s similar to 96.5-137.3 emu/g, coupled with a high yield strength, YS similar to 780-850 MPa, ultimate tensile strength, UTS similar to 1200 MPa, large tensile elongation, epsilon similar to 29-35%, and with desired high electrical resistivity (similar to 269.5-308.3 mu Omega.cm), making them attractive for high frequency electrical machines. Importantly, the latter HEA is further strengthened to a very high YS similar to 1140-1200 MPa with excellent ductility (epsilon similar to 18-25%) and electrical resistivity (296.1-459.3 mu Omega.cm), but at the cost of higher H-c values similar to 8.8-48.6 Oe.
Author
Sudip Kumar Sarkar
University of North Texas
Nachiket Keskar
University of North Texas
Li Ping Tan
Nanyang Technological University
Tirthesh Ingale
University of North Texas
Advika Chesetti
University of North Texas
Sriswaroop Dasari
University of North Texas
University of Texas
Karl P. Davidson
Curtin University
Nanyang Technological University
Varun Chaudhary
Chalmers, Industrial and Materials Science, Materials and manufacture
Narendra Dahotre
University of North Texas
R. V. Ramanujan
Nanyang Technological University
Rajarshi Banerjee
University of North Texas
Nanyang Technological University
Nature Communications
2041-1723 (ISSN) 20411723 (eISSN)
Vol. 17 1 2890Subject Categories (SSIF 2025)
Materials Chemistry
Metallurgy and Metallic Materials
Polymer Chemistry
Other Chemistry Topics
Inorganic Chemistry
DOI
10.1038/s41467-026-68891-6
PubMed
41644543