Mechanical and Microstructural Characterization of Powder Metallurgy CoCrNi Medium Entropy Alloy

Mechanical and Microstructural Characterization of Powder Metallurgy CoCrNi Medium Entropy Alloy

WoS Article

The present study is focused on synthesis and mechanical properties characterization of equiatomic CoCrNi medium entropy alloy (MEA). Powder metallurgy processes of mechanical alloying (MA) with subsequent spark plasma sintering (SPS) for bulk alloy densification have been utilized. As opposed to the single-phase alloys of identical composition fabricated via casting routes, the alloy after SPS compaction consisted of a major FCC solid solution phase (94.4%), minor fraction of secondary BCC phase (5.6%, precipitated at the FCC grains boundaries), and negligible amount of oxide inclusions. The alloy exhibited high ultimate tensile strength of 1024 MPa and a elongation to fracture of 26%. Elastic modulus of the alloy reached 222 GPa and the thermal expansion coefficient (CTE) was measured as 17.4×10−6 K−1 The plastic deformation in the alloy is carried out by a combination of dislocation glide and mechanical nano-twinning at room temperature.

The present study is focused on synthesis and mechanical properties characterization of equiatomic CoCrNi medium entropy alloy (MEA). Powder metallurgy processes of mechanical alloying (MA) with subsequent spark plasma sintering (SPS) for bulk alloy densification have been utilized. As opposed to the single-phase alloys of identical composition fabricated via casting routes, the alloy after SPS compaction consisted of a major FCC solid solution phase (94.4%), minor fraction of secondary BCC phase (5.6%, precipitated at the FCC grains boundaries), and negligible amount of oxide inclusions. The alloy exhibited high ultimate tensile strength of 1024 MPa and a elongation to fracture of 26%. Elastic modulus of the alloy reached 222 GPa and the thermal expansion coefficient (CTE) was measured as 17.4×10−6 K−1 The plastic deformation in the alloy is carried out by a combination of dislocation glide and mechanical nano-twinning at room temperature.

tensile test; mechanical alloying; plasticity; mechanical characterization; powder metallurgy

tensile test; mechanical alloying; plasticity; mechanical characterization; powder metallurgy

MORAVČÍK, I.; ČÍŽEK, J.; KOVACOVA, Z.; HORNÍK, V.; KUBĚNA, I.; KITZMANTEL, E.; NEJEZCHLEBOVÁ, J.; NEUBAUER, E.; DLOUHÝ, I.

2018

07.06.2017

Elsevier

London

0921-5093

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

2017

701

Swiss Confederation

370

380

11

https://doi.org/10.1016/j.msea.2017.06.086

1-s2.0-S0921509317308535-main