Application of Hydride Process in Achieving Equimolar TiNbZrHfTa BCC Refractory High Entropy Alloy
For the first time, an equiatomic refractory high entropy alloy (RHEA) TiNbZrHfTa compact with a single-phase body-centered cubic (BCC) structure was fabricated via a titanium hydride (TiH<sub>2</sub>) assisted powder metallurgy approach. The constituent pure Ti, Zr, Nb, Hf, and Ta powde...
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MDPI AG
2020-11-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/10/11/1020 |
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| author | Bhupendra Sharma Kentaro Nagano Kuldeep Kumar Saxena Hiroshi Fujiwara Kei Ameyama |
| author_facet | Bhupendra Sharma Kentaro Nagano Kuldeep Kumar Saxena Hiroshi Fujiwara Kei Ameyama |
| author_sort | Bhupendra Sharma |
| collection | DOAJ |
| description | For the first time, an equiatomic refractory high entropy alloy (RHEA) TiNbZrHfTa compact with a single-phase body-centered cubic (BCC) structure was fabricated via a titanium hydride (TiH<sub>2</sub>) assisted powder metallurgy approach. The constituent pure Ti, Zr, Nb, Hf, and Ta powders were mechanically alloyed (MA) with titanium hydride (TiH<sub>2</sub>) powder. The resultant MA powder was dehydrogenated at 1073 K for 3.6 ks and subsequently sintered through spark plasma sintering (SPS). Additionally, TiNbZrHfTa counterparts were prepared from pure elements without MA with TiH<sub>2</sub>. It was observed that the compact prepared from pure powders had a chemically heterogeneous microstructure with hexagonal close packed (HCP) and dual BCC phases. On the other hand, despite containing many constituents, the compact fabricated at 1473 K for 3.6 ks via the hydride approach had a single-phase BCC structure. The Vickers microhardness of the TiNbZrHfTa alloy prepared via the hydride process was Hv 520 (±30). The exceptional microhardness of the alloy is greater than any individual constituent, suggesting the operation of a simple solid-solution-like strengthening mechanism and/or precipitation hardening. In addition, the heat treatments were also carried out to analyze the phase stability of TiNbZrHfTa prepared via the hydride process. The results highlight the substantial changes in the phase as a function of temperature and/or time. |
| first_indexed | 2024-03-10T14:59:41Z |
| format | Article |
| id | doaj.art-43e8582516794e2287b051e83826aeb8 |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T14:59:41Z |
| publishDate | 2020-11-01 |
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| series | Crystals |
| spelling | doaj.art-43e8582516794e2287b051e83826aeb82023-11-20T20:16:58ZengMDPI AGCrystals2073-43522020-11-011011102010.3390/cryst10111020Application of Hydride Process in Achieving Equimolar TiNbZrHfTa BCC Refractory High Entropy AlloyBhupendra Sharma0Kentaro Nagano1Kuldeep Kumar Saxena2Hiroshi Fujiwara3Kei Ameyama4Research Organization of Science and Technology, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu-city, Shiga 525-8577, JapanGraduate School of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu-city, Shiga 525-8577, JapanFaculty of Mechanical Engineering, GLA University, NH-2, Mathura-Delhi Road P.O. Chaumuhan, Mathura 281-406, IndiaDepartment of Mechanical Engineering, Faculty of Science and Engineering, Shizuoka Institute of Science and Technology, Fukuroi, Shizuoka 437-8555, JapanFaculty of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu-city, Shiga 525-8577, JapanFor the first time, an equiatomic refractory high entropy alloy (RHEA) TiNbZrHfTa compact with a single-phase body-centered cubic (BCC) structure was fabricated via a titanium hydride (TiH<sub>2</sub>) assisted powder metallurgy approach. The constituent pure Ti, Zr, Nb, Hf, and Ta powders were mechanically alloyed (MA) with titanium hydride (TiH<sub>2</sub>) powder. The resultant MA powder was dehydrogenated at 1073 K for 3.6 ks and subsequently sintered through spark plasma sintering (SPS). Additionally, TiNbZrHfTa counterparts were prepared from pure elements without MA with TiH<sub>2</sub>. It was observed that the compact prepared from pure powders had a chemically heterogeneous microstructure with hexagonal close packed (HCP) and dual BCC phases. On the other hand, despite containing many constituents, the compact fabricated at 1473 K for 3.6 ks via the hydride approach had a single-phase BCC structure. The Vickers microhardness of the TiNbZrHfTa alloy prepared via the hydride process was Hv 520 (±30). The exceptional microhardness of the alloy is greater than any individual constituent, suggesting the operation of a simple solid-solution-like strengthening mechanism and/or precipitation hardening. In addition, the heat treatments were also carried out to analyze the phase stability of TiNbZrHfTa prepared via the hydride process. The results highlight the substantial changes in the phase as a function of temperature and/or time.https://www.mdpi.com/2073-4352/10/11/1020TiNbZrHfTaBCC structurerefractory high entropy alloystitanium hydridespark plasma sintering |
| spellingShingle | Bhupendra Sharma Kentaro Nagano Kuldeep Kumar Saxena Hiroshi Fujiwara Kei Ameyama Application of Hydride Process in Achieving Equimolar TiNbZrHfTa BCC Refractory High Entropy Alloy Crystals TiNbZrHfTa BCC structure refractory high entropy alloys titanium hydride spark plasma sintering |
| title | Application of Hydride Process in Achieving Equimolar TiNbZrHfTa BCC Refractory High Entropy Alloy |
| title_full | Application of Hydride Process in Achieving Equimolar TiNbZrHfTa BCC Refractory High Entropy Alloy |
| title_fullStr | Application of Hydride Process in Achieving Equimolar TiNbZrHfTa BCC Refractory High Entropy Alloy |
| title_full_unstemmed | Application of Hydride Process in Achieving Equimolar TiNbZrHfTa BCC Refractory High Entropy Alloy |
| title_short | Application of Hydride Process in Achieving Equimolar TiNbZrHfTa BCC Refractory High Entropy Alloy |
| title_sort | application of hydride process in achieving equimolar tinbzrhfta bcc refractory high entropy alloy |
| topic | TiNbZrHfTa BCC structure refractory high entropy alloys titanium hydride spark plasma sintering |
| url | https://www.mdpi.com/2073-4352/10/11/1020 |
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