High Temperature Deformation Behavior and Strengthening Mechanisms of Heat Resistant High Entropy Alloys
Abstract
In this research, two types of heat-resistant high entropy alloys were designed, fabricated and their mechanical behaviors and strengthening mechanisms were characterized. The high entropy superalloys (HESAs) were designed and fabricated by powder metallurgy process to have a novel microstructure of homogeneously distributed stable precipitates and dispersoids in FCC structured high entropy alloy matrices. The NiCoAlCrFeTi HESA with L12 precipitates and Y2O3 dispersoids showed higher yield strengths up to temperatures of 800C with good ductility at room temperature, compared to conventional Inconel 706 or Incoloy 901. The NiCoAlCrFeTi based HESAs could be good candidate materials for heat-resistant application up to elevated temperature of 800C.The AlxCrNbVMo based refractory high entropy alloys (RHEAs) were designed and fabricated to exhibit a novel microstructure of stable nano-sized NbO1-x or Al2O3 dispersoids in BCC structured high entropy alloy matrices fabricated by powder metallurgy process. The nano-sized dispersoids were uniformly distributed by in-situ reaction process during mechanical alloying and sintering. The AlxCrNbVMo based RHEAs exhibited superior specific yield strength showing 87 enhancement at 1,000C compared to that of AlMoNbTaTiZr HEA, which exhibited the best specific yield strength among the cast RHEAs. Our designed RHEAs show much higher specific yield strengths compared to those of Ni-based superalloys up to temperatures of 1000C. The AlxCrNbVMo based RHEAs could be promising candidate materials for heat-resistant application up to elevated temperature of 1,000C or higher.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 19, 2022
- Accession Number
- AD1194100
Entities
People
- Soon H. Hong
Organizations
- KAIST