Solidification Microstructures of the Ingots Obtained by Arc Melting and Cold Crucible Levitation Melting in TiNbTaZr Medium-Entropy Alloy and TiNbTaZrX (X = V, Mo, W) High-Entropy Alloys
The solidification microstructures of the TiNbTaZr medium-entropy alloy and TiNbTaZrX (X = V, Mo, and W) high-entropy alloys (HEAs), including the TiNbTaZrMo bio-HEA, were investigated. Equiaxed dendrite structures were observed in the ingots that were prepared by arc melting, regardless of the posi...
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doaj-f0febf49fc504602b68873f1da3180412020-11-24T21:29:03ZengMDPI AGEntropy1099-43002019-05-0121548310.3390/e21050483e21050483Solidification Microstructures of the Ingots Obtained by Arc Melting and Cold Crucible Levitation Melting in TiNbTaZr Medium-Entropy Alloy and TiNbTaZrX (X = V, Mo, W) High-Entropy AlloysTakeshi Nagase0Kiyoshi Mizuuchi1and Takayoshi Nakano2Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Ibaraki, Osaka 567-0047, JapanOsaka Research Institute of Industrial Science and Technology, 1-6-50 Morinomiya, Joto-ku,Osaka 536-8553, JapanDivision of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, JapanThe solidification microstructures of the TiNbTaZr medium-entropy alloy and TiNbTaZrX (X = V, Mo, and W) high-entropy alloys (HEAs), including the TiNbTaZrMo bio-HEA, were investigated. Equiaxed dendrite structures were observed in the ingots that were prepared by arc melting, regardless of the position of the ingots and the alloy system. In addition, no significant difference in the solidification microstructure was observed in TiZrNbTaMo bio-HEAs between the arc-melted (AM) ingots and cold crucible levitation melted (CCLM) ingots. A cold shut was observed in the AM ingots, but not in the CCLM ingots. The interdendrite regions tended to be enriched in Ti and Zr in the TiNbTaZr MEA and TiNbTaZrX (X = V, Mo, and W) HEAs. The distribution coefficients during solidification, which were estimated by thermodynamic calculations, could explain the distribution of the constituent elements in the dendrite and interdendrite regions. The thermodynamic calculations indicated that an increase in the concentration of the low melting-temperature V (2183 K) leads to a monotonic decrease in the liquidus temperature<i> </i>(<i>T</i><sub>L</sub>), and that increases in the concentration of high melting-temperature Mo (2896 K) and W (3695 K) lead to a monotonic increase in <i>T</i><sub>L</sub> in TiNbTaZrX<sub>x</sub> (X = V, Mo, and W) (<i>x</i><i> </i><i> </i>=  0 − 2) HEAs.https://www.mdpi.com/1099-4300/21/5/483high-entropy alloybiomaterialsarc meltinglevitation meltingmicrostructuresolidificationthermodynamic calculation |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Takeshi Nagase Kiyoshi Mizuuchi and Takayoshi Nakano |
spellingShingle |
Takeshi Nagase Kiyoshi Mizuuchi and Takayoshi Nakano Solidification Microstructures of the Ingots Obtained by Arc Melting and Cold Crucible Levitation Melting in TiNbTaZr Medium-Entropy Alloy and TiNbTaZrX (X = V, Mo, W) High-Entropy Alloys Entropy high-entropy alloy biomaterials arc melting levitation melting microstructure solidification thermodynamic calculation |
author_facet |
Takeshi Nagase Kiyoshi Mizuuchi and Takayoshi Nakano |
author_sort |
Takeshi Nagase |
title |
Solidification Microstructures of the Ingots Obtained by Arc Melting and Cold Crucible Levitation Melting in TiNbTaZr Medium-Entropy Alloy and TiNbTaZrX (X = V, Mo, W) High-Entropy Alloys |
title_short |
Solidification Microstructures of the Ingots Obtained by Arc Melting and Cold Crucible Levitation Melting in TiNbTaZr Medium-Entropy Alloy and TiNbTaZrX (X = V, Mo, W) High-Entropy Alloys |
title_full |
Solidification Microstructures of the Ingots Obtained by Arc Melting and Cold Crucible Levitation Melting in TiNbTaZr Medium-Entropy Alloy and TiNbTaZrX (X = V, Mo, W) High-Entropy Alloys |
title_fullStr |
Solidification Microstructures of the Ingots Obtained by Arc Melting and Cold Crucible Levitation Melting in TiNbTaZr Medium-Entropy Alloy and TiNbTaZrX (X = V, Mo, W) High-Entropy Alloys |
title_full_unstemmed |
Solidification Microstructures of the Ingots Obtained by Arc Melting and Cold Crucible Levitation Melting in TiNbTaZr Medium-Entropy Alloy and TiNbTaZrX (X = V, Mo, W) High-Entropy Alloys |
title_sort |
solidification microstructures of the ingots obtained by arc melting and cold crucible levitation melting in tinbtazr medium-entropy alloy and tinbtazrx (x = v, mo, w) high-entropy alloys |
publisher |
MDPI AG |
series |
Entropy |
issn |
1099-4300 |
publishDate |
2019-05-01 |
description |
The solidification microstructures of the TiNbTaZr medium-entropy alloy and TiNbTaZrX (X = V, Mo, and W) high-entropy alloys (HEAs), including the TiNbTaZrMo bio-HEA, were investigated. Equiaxed dendrite structures were observed in the ingots that were prepared by arc melting, regardless of the position of the ingots and the alloy system. In addition, no significant difference in the solidification microstructure was observed in TiZrNbTaMo bio-HEAs between the arc-melted (AM) ingots and cold crucible levitation melted (CCLM) ingots. A cold shut was observed in the AM ingots, but not in the CCLM ingots. The interdendrite regions tended to be enriched in Ti and Zr in the TiNbTaZr MEA and TiNbTaZrX (X = V, Mo, and W) HEAs. The distribution coefficients during solidification, which were estimated by thermodynamic calculations, could explain the distribution of the constituent elements in the dendrite and interdendrite regions. The thermodynamic calculations indicated that an increase in the concentration of the low melting-temperature V (2183 K) leads to a monotonic decrease in the liquidus temperature<i> </i>(<i>T</i><sub>L</sub>), and that increases in the concentration of high melting-temperature Mo (2896 K) and W (3695 K) lead to a monotonic increase in <i>T</i><sub>L</sub> in TiNbTaZrX<sub>x</sub> (X = V, Mo, and W) (<i>x</i><i> </i><i> </i>=  0 − 2) HEAs. |
topic |
high-entropy alloy biomaterials arc melting levitation melting microstructure solidification thermodynamic calculation |
url |
https://www.mdpi.com/1099-4300/21/5/483 |
work_keys_str_mv |
AT takeshinagase solidificationmicrostructuresoftheingotsobtainedbyarcmeltingandcoldcruciblelevitationmeltingintinbtazrmediumentropyalloyandtinbtazrxxvmowhighentropyalloys AT kiyoshimizuuchi solidificationmicrostructuresoftheingotsobtainedbyarcmeltingandcoldcruciblelevitationmeltingintinbtazrmediumentropyalloyandtinbtazrxxvmowhighentropyalloys AT andtakayoshinakano solidificationmicrostructuresoftheingotsobtainedbyarcmeltingandcoldcruciblelevitationmeltingintinbtazrmediumentropyalloyandtinbtazrxxvmowhighentropyalloys |
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