Berlin 2015 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 14: Transport I: Diffusion
MM 14.2: Talk
Monday, March 16, 2015, 16:00–16:15, H 0107
Phase composition, microstructure and Ni tracer diffusion in FCC FeCrCoNi-based high entropy alloys — •Mayur Vaidya1,2, Simon Trubel2, Igor Golovin3, Buduraju Srinivasa Murty1, Sergiy Divinski2,3, and Gerhard Wilde2 — 1Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, India — 2Institute of Material Physics, University of Muenster, Muenster, Germany — 3National University of Science and Technology MISiS, Moscow, Russia
High entropy alloys (HEAs) CoCrFeNi, CoCrFeMnNi and CoCrFeMnNiV were prepared by arc melting the constituent elements, followed by homogenization at 1200∘C for 50 h. XRD results show that CoCrFeNi and CoCrFeMnNi represent single phase FCC phases, while CoCrFeMnNiV comprises of FCC and tetragonal phases. EBSD analysis confirms a single phase structure, uniform composition and a grain size in excess of 250µm in CoCrFeNi and CoCrFeMnNi alloys. Elemental X-ray maps of CoCrFeMnNiV substantiate its decomposition into a Ni- and Mn-rich phase (located predominantly at grain boundaries) and a V- and Cr-rich phase. Such FCC-HEAs have been explored for high temperature applications, for which creep behavior and in turn the diffusion kinetics of these alloys must be understood. We are studying Ni tracer diffusion in these HEAs using 63Ni radioisotope. Ni diffusion kinetics, amplitude- and temperature dependent mechanical damping in HEAs are reported. Partial support by the Ministry of Education and Science of Russia in the framework of Increase Competitiveness Program of NUST MISiS(K3-2014-045) is acknowledged.