MAE Seminar: Ian Baker

Title:

An Overview of FeNiMnAl(Cr) High Entropy Alloys

Abstract:

FeNiMnAlCr high entropy alloys have been investigated since 2004 with a focus on producing economical materials for both high-temperature and cryogenic applications. Four different types of microstructures have been investigated: (1) ultrastrong, ultrafine (5-50 nm) spinodally-formed microstructures in Fe₃₀Ni₂₀Mn₂₀Al₃₀, Fe₂₅Ni₂₅Mn₂₀Al₃₀ and Fe₃₅Ni₁₅Mn₂₅Al₂₅, which consist of (Fe, Mn)-rich B2-ordered (ordered b.c.c.), and (Ni, Al)-rich L2₁-ordered (Heusler) phases, and in Fe₃₀Ni₂₀Mn₂₅Al₂₅ (Ni,Al)-rich, which consists of B2 and (Fe,Mn)-rich b.c.c. phases, aligned along <100>; (2) strong but brittle fine eutectoid microstructures in Fe₃₀Ni₂₀Mn₃₀Al₂₀, Fe₂₅Ni₂₅Mn₃₀Al₂₀, and Fe₂₈Ni₁₈Mn₃₃Al₂₁ consisting of alternating (Fe, Mn)-rich f.c.c. and (Ni, Al)-rich B2 plates with an orientation relationship close to f.c.c.(002)//B2(002): f.c.c.(011)//B2(001); (3) strong, ductile lamellar eutectic microstructures present in Fe₃₀Ni₂₀Mn₃₅Al₁₅, Fe₂₉Ni₁₉Mn₃₈Al₁₄ and Fe₃₁Ni₁₈Mn₃₈Al₁₃ consisting of alternating (Fe, Mn)-rich f.c.c. and (Ni, Al)-rich B2 phases with a Kurdjumov-Sachs orientation relationship between the phases (Cr was also added to some alloys); and (4) a very-ductile single-phase f.c.c. alloy Fe_40.4Ni_11.3Mn_34.8Al_7.5Cr₆. The effects of temperature on the quasi-static mechanical properties have been studied at temperatures from 4.2 K to 1073 K. The creep behavior and dry sliding wear behavior have also been studied at a variety of temperatures The effects of nitriding; solute additions such as titanium or interstitials such as carbon or boron; recrystallization, and production by additive manufacturing have been explored. This presentation will outline the microstructures (before and after mechanical testing) and mechanical properties of these alloys along with current applications that are being pursued in concentrated solar power and for cryogenic use.

Bio:

After completing a B.A. and D. Phil. In Metallurgy and Science of Materials at the University of Oxford, Dr. Ian Baker joined the Faculty of the Thayer School of Engineering at Dartmouth College in 1982, where he is currently the Sherman Fairchild Professor of Engineering.  He was Chair of Engineering Sciences (1996-2000); M.S./Ph.D. Program Director (2000-2005); Director of the NIST-funded Center for Nanomaterials Research at Dartmouth (2002-2005); Director of the NIH-funded Center for Cancer Nanotechnology Excellence on Magnetic Hyperthermia (2011-2016), Senior Associate Dean for Academic Affairs (2005-2019); and is currently the Senior Associate Dean for Research and Graduate Education.  Dr. Baker was a CASE – NASA Co-operative Aerospace R&D Fellow at NASA-Lewis Research Center, Cleveland, OH, in summer 2005 and 2006, and Principal Research Metallurgist, Sherritt-Gordon Ltd., Fort Saskatchewan, Alberta in 1991. He is a Chartered Engineer (U.K.), and a Fellow of ASM international, TMS, MRS, IOMMM (U.K.) and AAAS. He was Editor-in-Chief of the journal Materials Characterization from 2008-2020, and is currently the co-Editor in Chief of the journal High Entropy Alloys and Materials, and the Field Chief Editor for the Journal Frontiers in Metals and Alloys. He has published around 500 papers and articles and one book entitled “Fifty Materials that Make the World”. He has given over 400 presentations at conferences, universities, and to industry.  He has organized several conferences on snow firn, ice and intermetallic compounds. He

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