Composition-dependent apparent activation-energy and sluggish grain-growth in high entropy alloys. Issue 7 (3rd July 2019)

• Record Type: Journal Article
• Authors: Gwalani, B.; Salloom, R.; Alam, T.; Valentin, S. G.; Zhou, X.; Thompson, G.; Srinivasan, S. G.; Banerjee, R.
• Is Part Of: Materials research letters. Volume 7:Issue 7(2019)
• Page Start: 267
• Page End: 274
• Publication Date: 2019-07-03
• Subjects: High entropy alloy -- grain-growth -- activation-energy -- atom-Probe tomography; Materials science -- Research -- Periodicals; Biomedical materials -- Research -- Periodicals; Composite materials -- Research -- Periodicals; Biomedical materials -- Research; Composite materials -- Research; Materials science -- Research; Periodicals; 620.1105
• DOI: 10.1080/21663831.2019.1601644
• Languages: English
• ISSNs: 2166-3831

Abstract

ABSTRACT: Experimental results reveal that the apparent activation-energy for grain-growth in an fcc- based Alx CoCrFeNi high entropy alloy (HEA) system increases from 179 to 486 kJ/mol when the Al content increases from x = 0.1 to 0.3. These unexpectedly high apparent activation-energy values can be potentially attributed to solute clustering within the fcc solid-solution phase that develops with increasing Al content in this HEA. Detailed microstructural analysis using atom-probe tomography and density functional theory (DFT) calculations strongly indicate the presence of such nanoscale clusters. This phenomenon can change grain-growth from a classical solute-drag regime to a much more sluggish cluster-drag based mechanism in these HEAs. GRAPHICAL ABSTRACT: IMPACT STATEMENT: First report on a composition dependent change in apparent activation-energy for grain-growth in high entropy alloys. A novel cluster drag effect inhibiting grain-growth kinetics is suggested.