Phase structures of gas atomized equiatomic CrFeNiMn high entropy alloy powder

Joonas Lehtonen*, Yanling Ge, Nevaf Ciftci, Oleg Heczko, Volker Uhlenwinkel, Simo Pekka Hannula

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)

Abstract

In powder technologies such as sintering, 3-D printing, and thermal spraying, the characteristics of the powders are of uttermost importance. This holds for composition as well as for phase and grain structure. In this work, we characterize argon gas atomized Cr25.2Fe24.8Ni25.5Mn24.5 high entropy alloy powder, which is a material of high interest for applications requiring high strength and radiation resistance. The microstructure of gas atomized particles at different class sizes is characterized and the powder properties are determined by nanoindentation and magnetic measurements. The atomized particles have a smooth spherical shape with a fine surface pattern. The composition and phase structure as well as hardness and magnetic properties are particle size dependent, i.e., depend on cooling rate during atomization. The phase structure of the atomized powder is nearly single FCC phase with a small amount of BCC phase, the amount of which increased with the decreasing powder particle size. Average nanohardness determined from nanoindentation of particle class sizes <20 μm and 90–150 μm are 4.25 ± 0.73 GPa and 3.96 ± 0.60 GPa, respectively. The particles are paramagnetic at room temperature, but at 10 K an increasing ferromagnetic contribution is observed with decreasing powder particle size and increasing fraction of dispersed BCC phase. The Curie point of this soft magnetic phase is about 205 K.

Original languageEnglish
Article number154142
Number of pages7
JournalJournal of Alloys and Compounds
Volume827
DOIs
Publication statusPublished - 25 Jun 2020
MoE publication typeA1 Journal article-refereed

Keywords

  • Gas atomization
  • High entropy alloy
  • Magnetic properties
  • Mechanical properties
  • Microstructure
  • Powder metallurgy

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