Effect of titanium in-situ alloying on the microstructure and mechanical properties of the RHEAs MoNbTaW system
Refractory high-entropy refractory alloys (RHEAs) are emerging as potential alternatives to Ni-based superalloys due to their exceptional high-temperature properties. Among them, the MoNbTaW system shows promising characteristics, though brittleness at room temperature limits practical use. In the p...
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Taylor & Francis Group
2025-12-01
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| Series: | European Journal of Materials |
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| Online Access: | https://www.tandfonline.com/doi/10.1080/26889277.2025.2480834 |
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| author | Bernardo. L. Ribeiro Peter Grün Filofteia-Laura Toma Leonid Gerdt Joerg Kaspar Maria Barbosa Rúben F. Santos Elsa W. Sequeiros |
| author_facet | Bernardo. L. Ribeiro Peter Grün Filofteia-Laura Toma Leonid Gerdt Joerg Kaspar Maria Barbosa Rúben F. Santos Elsa W. Sequeiros |
| author_sort | Bernardo. L. Ribeiro |
| collection | DOAJ |
| description | Refractory high-entropy refractory alloys (RHEAs) are emerging as potential alternatives to Ni-based superalloys due to their exceptional high-temperature properties. Among them, the MoNbTaW system shows promising characteristics, though brittleness at room temperature limits practical use. In the present study, the titanium (Ti) in-situ alloying through Laser Direct Energy Deposition (L-DED), combined with thermodynamical calculations for phase prediction, presented as a high-throughput screening methodology to gather immense new information on RHEAs based on the MoNbTaWTi system. Thermodynamic calculations showcase that the addition of Ti, up to 50 at. %, allow a single-phase BCC structure. Experimentally, it was observed that most Ti additions lead to sustaining the BCC structure; however, due to Ti’s lower melting point, some interdendritic heterogeneity was observed. EBSD analysis shows that the alloying with Ti can lead to an exchange in predominant crystallographic orientation while presenting no significant effect on the grain size. Microhardness tests show that the highest hardness increase is obtained for ∼24 at% of Ti, linked to a solid solution strengthening. Based on these results, it was possible to qualify L-DED as a RHEAs screening technology and expand the practical knowledge of these alloys, thus accelerating their potential application in aerospace applications. |
| format | Article |
| id | doaj-art-29d804cd05824c2fb325ce4f57a3e9af |
| institution | Kabale University |
| issn | 2688-9277 |
| language | English |
| publishDate | 2025-12-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | European Journal of Materials |
| spelling | doaj-art-29d804cd05824c2fb325ce4f57a3e9af2025-08-20T03:39:54ZengTaylor & Francis GroupEuropean Journal of Materials2688-92772025-12-015110.1080/26889277.2025.2480834Effect of titanium in-situ alloying on the microstructure and mechanical properties of the RHEAs MoNbTaW systemBernardo. L. Ribeiro0Peter Grün1Filofteia-Laura Toma2Leonid Gerdt3Joerg Kaspar4Maria Barbosa5Rúben F. Santos6Elsa W. Sequeiros7LAETA/INEGI – Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, PortugalFraunhofer Institute for Material and Beam Technology IWS, Dresden, GermanyFraunhofer Institute for Material and Beam Technology IWS, Dresden, GermanyFraunhofer Institute for Material and Beam Technology IWS, Dresden, GermanyFraunhofer Institute for Material and Beam Technology IWS, Dresden, GermanyLAETA/INEGI – Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, PortugalLAETA/INEGI – Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, PortugalLAETA/INEGI – Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, PortugalRefractory high-entropy refractory alloys (RHEAs) are emerging as potential alternatives to Ni-based superalloys due to their exceptional high-temperature properties. Among them, the MoNbTaW system shows promising characteristics, though brittleness at room temperature limits practical use. In the present study, the titanium (Ti) in-situ alloying through Laser Direct Energy Deposition (L-DED), combined with thermodynamical calculations for phase prediction, presented as a high-throughput screening methodology to gather immense new information on RHEAs based on the MoNbTaWTi system. Thermodynamic calculations showcase that the addition of Ti, up to 50 at. %, allow a single-phase BCC structure. Experimentally, it was observed that most Ti additions lead to sustaining the BCC structure; however, due to Ti’s lower melting point, some interdendritic heterogeneity was observed. EBSD analysis shows that the alloying with Ti can lead to an exchange in predominant crystallographic orientation while presenting no significant effect on the grain size. Microhardness tests show that the highest hardness increase is obtained for ∼24 at% of Ti, linked to a solid solution strengthening. Based on these results, it was possible to qualify L-DED as a RHEAs screening technology and expand the practical knowledge of these alloys, thus accelerating their potential application in aerospace applications.https://www.tandfonline.com/doi/10.1080/26889277.2025.2480834In-situ alloyinglaser direct energy depositionmicrostructureMoNbTaWTiRHEAs |
| spellingShingle | Bernardo. L. Ribeiro Peter Grün Filofteia-Laura Toma Leonid Gerdt Joerg Kaspar Maria Barbosa Rúben F. Santos Elsa W. Sequeiros Effect of titanium in-situ alloying on the microstructure and mechanical properties of the RHEAs MoNbTaW system European Journal of Materials In-situ alloying laser direct energy deposition microstructure MoNbTaWTi RHEAs |
| title | Effect of titanium in-situ alloying on the microstructure and mechanical properties of the RHEAs MoNbTaW system |
| title_full | Effect of titanium in-situ alloying on the microstructure and mechanical properties of the RHEAs MoNbTaW system |
| title_fullStr | Effect of titanium in-situ alloying on the microstructure and mechanical properties of the RHEAs MoNbTaW system |
| title_full_unstemmed | Effect of titanium in-situ alloying on the microstructure and mechanical properties of the RHEAs MoNbTaW system |
| title_short | Effect of titanium in-situ alloying on the microstructure and mechanical properties of the RHEAs MoNbTaW system |
| title_sort | effect of titanium in situ alloying on the microstructure and mechanical properties of the rheas monbtaw system |
| topic | In-situ alloying laser direct energy deposition microstructure MoNbTaWTi RHEAs |
| url | https://www.tandfonline.com/doi/10.1080/26889277.2025.2480834 |
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