An oxidation resistance study has been made on Nb-Cr-V-W-Ta high entropy alloy in a range of temperature from 600 to 1400℃in air.Static oxidation study has been performed for either(a)12 or 24 h of heating time or(b)...An oxidation resistance study has been made on Nb-Cr-V-W-Ta high entropy alloy in a range of temperature from 600 to 1400℃in air.Static oxidation study has been performed for either(a)12 or 24 h of heating time or(b)3 or 10℃/min heating rates to the desired oxidation temperature.Cyclic oxidation study conducted for three and a half days has been conducted at 600,700,and 800℃using 12 h of heating cycles.The alloy can withstand the cyclic oxidation process with only a reasonable loss of alloy.The identification of oxides indicates crystals of W and Ta oxides in cylindrical form while Nb and Cr oxides show a nodular or granular morphology at both 1000 and 1200℃while and additional of oxide of V in whisker forms at 1200℃.展开更多
A Nb-Cr-V-W-Ta high entropy alloy has been subjected to annealing treatment at 600,700 and 800℃in air for 6 h.Five different phases have been identified based on their composition in the as received condition.The ann...A Nb-Cr-V-W-Ta high entropy alloy has been subjected to annealing treatment at 600,700 and 800℃in air for 6 h.Five different phases have been identified based on their composition in the as received condition.The annealing treatment does not alter the phase analysis and compositions except for the W-rich phase where minor changes in the composition have been observed.This is considered as an experimental evidence of sluggish diffusivity associated with HEAs.Absence of phase transformation during the heating and the minimal changes in observed compositions of the phases is an indication of the resistance to diffusion offered by the elements of the high entropy alloy.Scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and color X-ray elemental mapping have been used to conduct this research.展开更多
基金support from the National Science Foundation with NSF-PREM grant#DMR-1827745.
文摘An oxidation resistance study has been made on Nb-Cr-V-W-Ta high entropy alloy in a range of temperature from 600 to 1400℃in air.Static oxidation study has been performed for either(a)12 or 24 h of heating time or(b)3 or 10℃/min heating rates to the desired oxidation temperature.Cyclic oxidation study conducted for three and a half days has been conducted at 600,700,and 800℃using 12 h of heating cycles.The alloy can withstand the cyclic oxidation process with only a reasonable loss of alloy.The identification of oxides indicates crystals of W and Ta oxides in cylindrical form while Nb and Cr oxides show a nodular or granular morphology at both 1000 and 1200℃while and additional of oxide of V in whisker forms at 1200℃.
基金The funding for research was provided by the National Science Foundation with NSF-PREM grant#DMR-1827745。
文摘A Nb-Cr-V-W-Ta high entropy alloy has been subjected to annealing treatment at 600,700 and 800℃in air for 6 h.Five different phases have been identified based on their composition in the as received condition.The annealing treatment does not alter the phase analysis and compositions except for the W-rich phase where minor changes in the composition have been observed.This is considered as an experimental evidence of sluggish diffusivity associated with HEAs.Absence of phase transformation during the heating and the minimal changes in observed compositions of the phases is an indication of the resistance to diffusion offered by the elements of the high entropy alloy.Scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and color X-ray elemental mapping have been used to conduct this research.
