Effect of second phase particles on mechanical properties and grain growth in a CoCrFeMnNi high entropy alloy

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

卷:748

Article

Klimova, M. V.¹  Shaysultanov, D. G.¹  Zherebtsov, S. V.¹  Stepanov, N. D.¹ 

[1] Belgorod Natl Res Univ, Lab Bulk Nanostruct Mat, Pobeda 85, Belgorod 308015, Russia

关键词: High entropy alloys;    Phase transformations;    Grains and interfaces;    Electron microscopy;    Stress/strain measurements;   

DOI  :  10.1016/j.msea.2019.01.112

来源: Elsevier

【 摘 要 】

Effect of annealing of a cold-worked CoCrFeMnNi alloy at temperatures of 500-900 degrees C for 1-50 h on the structure and mechanical properties was studied in the present work. Annealing for an hour resulted in: i) recrystallization of the face-centered cubic (fcc) matrix at 600-900 degrees C; ii) precipitation of a Cr-rich body-centered cubic (bcc) phase at 500-700 degrees C or a sigma phase particles at 600-800 degrees C. Moreover, an increase in the annealing time to 50 h at 600 degrees C resulted in a continuous growth of both the fcc grans and bcc/sigma particles and in an increase in the fraction of the sigma phase at the expense of the bcc phase particles. The fcc grains growth was found to be controlled by the pinning effect of the second phase particles. Soaking for an hour at 500-600 degrees C resulted in a substantial increase in strength of the alloy due to the second phases precipitation. Meanwhile annealing at the higher temperatures as well as an increase in the annealing time at 600 degrees C resulted in softening; however, even after 50 h annealing, the alloy demonstrated reasonably high strength. In the latter case fine fcc grains, preserved due to the pinning effect by the second phases particles, contributed to strength mainly.

【 授权许可】

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