Equbal, A
(2015)
Synthesis and Sintering Kinetics of Mechanically Alloyed FeCrCoMnNi High Entropy Alloy Powders.
Masters thesis, Indian Institute of Technology Hyderabad.
Abstract
High entropy alloys (HEAs) are solid solution of multi elements system fabricated in equiatomic or near equiatomic composition. These can be fabricated through two processing routes, melting-casting and mechanical alloying (MA). Objectives of this investigation are
to synthesize the high purity single phase FeCrCoMnNi HEA powder the mechanical alloying, and to study the sintering kinetics of this alloy powder. Elemental powders of Fe, Cr, Co, Mn and Ni were taken in equi-molar ratio and milled upto 15h using tungsten carbide vials and balls. XRD characterization of milled powders shows that high entropy alloy phase started forming at about 10h of milling; mostly with FCC phase. Milled powders were further characterized using differential scanning calorimetry(DSC) to understand the phase formation behavior during heating. The DSC analysis indicates that the exothermic reactions were occurred at about 470ºC, which may be attributed to the release of internal strains, accumulated during high energy ball milling and release of some dislocations and defects generated during milling. An end of thermic peak at
990ºC, which could be attributed to melting of some intermetallics phases. Post-mechanical alloying annealing treatment upto 1000ºC showed retention of the FCC phases.
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