Developing a single-phase and nanograined refractory high-entropy alloy ZrHfNbTaW with ultrahigh hardness by phase transformation via high-pressure torsion
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| Format: | Preprint |
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2024
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| _version_ | 1866929648590389248 |
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| author | Dangwal, Shivam Edalati, Kaveh |
| author_facet | Dangwal, Shivam Edalati, Kaveh |
| contents | High-entropy alloys (HEAs) are potential candidates for applications as refractory materials. While dual-phase refractory HEAs containing an ordered phase exhibit high hardness, there is high interest in developing intermetallic-free and single-phase refractory HEAs with high hardness. In this study, a new equiatomic HEA ZrHfNbTaW with an ultrahigh hardness of 860 Hv is developed. The alloy is first synthesized with a dual-phase structure via arc melting and further homogenized to a single body-centered cubic (BCC) structure by phase transformation via high-pressure torsion (HPT), using the concept of ultra-severe plastic deformation process. The ultrahigh hardness of the alloy, which is higher than those reported for refractory alloys and single-phase HEAs, is attributed to (i) solution hardening by severe lattice distortion, (ii) Hall-Petch grain boundary hardening by the formation of nanograins with 12 nm average size, and (iii) dislocation hardening confirmed by high-resolution transmission electron microscopy. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_19006 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Developing a single-phase and nanograined refractory high-entropy alloy ZrHfNbTaW with ultrahigh hardness by phase transformation via high-pressure torsion Dangwal, Shivam Edalati, Kaveh Materials Science High-entropy alloys (HEAs) are potential candidates for applications as refractory materials. While dual-phase refractory HEAs containing an ordered phase exhibit high hardness, there is high interest in developing intermetallic-free and single-phase refractory HEAs with high hardness. In this study, a new equiatomic HEA ZrHfNbTaW with an ultrahigh hardness of 860 Hv is developed. The alloy is first synthesized with a dual-phase structure via arc melting and further homogenized to a single body-centered cubic (BCC) structure by phase transformation via high-pressure torsion (HPT), using the concept of ultra-severe plastic deformation process. The ultrahigh hardness of the alloy, which is higher than those reported for refractory alloys and single-phase HEAs, is attributed to (i) solution hardening by severe lattice distortion, (ii) Hall-Petch grain boundary hardening by the formation of nanograins with 12 nm average size, and (iii) dislocation hardening confirmed by high-resolution transmission electron microscopy. |
| title | Developing a single-phase and nanograined refractory high-entropy alloy ZrHfNbTaW with ultrahigh hardness by phase transformation via high-pressure torsion |
| topic | Materials Science |
| url | https://arxiv.org/abs/2412.19006 |