Effect of Heat Treatment on the Microstructure and Mechanical Properties of Ti–6Al–4V Alloy Produced by L-PBF and PA-DED
Abstract
1. Introduction
2. Materials and Methods
2.1. L-PBF
2.2. PA-DED
2.3. Heat Treatment
2.4. Microstructural Investigation
2.5. Mechanical Testing
3. Results
3.1. As-Built Microstructure
3.2. Effect of Heat Treatment on the Microstructure
3.2.1. Stress-Relief Annealing
3.2.2. Subtransus Annealing
3.2.3. Solution Treatment and Aging
3.3. Mechanical Properties
4. Discussion
5. Conclusions
- It was established that L-PBF forms a non-equilibrium martensitic structure with a high defect density in the alloy, which provides high strength at low ductility. In contrast, PA-DED forms an equilibrium Widmanstätten (α + β) structure, which exhibits moderate strength and high ductility.
- It was shown that stress-relief annealing does not lead to noticeable microstructural changes; an increase in ductility is observed while strength is preserved.
- It was revealed that subtransus annealing forms an equilibrium lamellar (α + β) structure, after which both alloys become nearly isotropic in strength and their ductility increases substantially.
- It was established that solution treatment and aging (STA) form a bimodal structure, but its effect is fundamentally different: for L-PBF it provides high strength with adequate ductility, whereas for PA-DED it drastically increases strength but severely reduces the ductility of horizontal samples.
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
Abbreviations
| AC | Air cooling |
| BCC | Body centered cubic |
| BSEs | Backscattered electrons |
| EBM | Electron beam melting |
| EBSD | Electron backscatter diffraction |
| EDS | Energy dispersive X-ray spectroscopy |
| EL | Elongation |
| FC | Furnace cooling |
| HCP | Hexagonal close packed |
| HT | Heat treatment |
| L-PBF | Laser powder bed fusion |
| PA-DED | Plasma arc directed energy deposition |
| PBF | Powder bed fusion |
| SEM | Scanning electron microscopy |
| STA | Solution treatment and aging |
| TEM | Transmission electron microscopy |
| uEL | Uniform elongation |
| UTS | Ultimate tensile strength |
| WA-DED | Wire arc directed energy deposition |
| WQ | Water quenching |
| YS | Yield strength |
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| Ti | Al | V | Fe | Other |
|---|---|---|---|---|
| 90.5 ± 0.3 | 5.7 ± 0.2 | 3.6 ± 0.3 | 0.2 ± 0.1 | <0.1 |
| Ti | Al | V | Fe | Other |
|---|---|---|---|---|
| 90.2 ± 0.2 | 5.8 ± 0.1 | 4.0 ± 0.2 | 0.2 ± 0.1 | <0.1 |
| Treatment | UTS, MPa | YS, MPa | uEL, % | EL, % | |||||
|---|---|---|---|---|---|---|---|---|---|
| L-PBF [this study] | V | H | V | H | V | H | V | H | |
| As-built | 1395 ± 10 | 1275 ± 12 | 1282 ± 10 | 1111 ± 15 | 2 ± 0.2 | 2 ± 0.2 | 4.8 ± 1.2 | 3.3 ± 0.5 | |
| Stress relief annealing | 1317 ± 7 | 1273 ± 5 | 1253 ± 7 | 1190 ± 8 | 2.2 ± 0.2 | 2.5 ± 0.2 | 6.3 ± 1 | 3.7 ± 0.5 | |
| Subtransus annealing | 1042 ± 5 | 1042 ± 5 | 985 ± 12 | 970 ± 6 | 7 ± 0.1 | 8.1 ± 0.6 | 15.6 ± 1 | 14.4 ± 1 | |
| STA | 1157 ± 12 | 1141 ± 10 | 1127 ± 10 | 1075 ± 5 | 4.2 ± 0.1 | 3.9 ± 0.2 | 8.9 ± 0.5 | 11.5 ± 0.6 | |
| PA-DED [this study] | As-built | 930 ± 7 | 942 ± 3 | 882 ± 10 | 874 ± 4 | 3.6 ± 0.5 | 7.2 ± 0.5 | 6.7 ± 1.5 | 8.9 ± 2.3 |
| Stress relief annealing | 927 ± 10 | 948 ± 5 | 834 ± 7 | 850 ± 8 | 7.7 ± 1.5 | 5.2 ± 0.5 | 18 ± 4 | 10 ± 2 | |
| Subtransus annealing | 941 ± 5 | 942 ± 6 | 890 ± 8 | 860 ± 10 | 4 ± 0.1 | 10.6 ± 1.2 | 10.4 ± 2 | 16.5 ± 3 | |
| STA | 1130 ± 10 | 1064 ± 5 | 1027 ± 5 | 980 ± 6 | 3.6 ± 0.1 | 3.5 ± 0.1 | 13.6 ± 2 | 5 ± 1.5 | |
| L-PBF | As-built [26,31,32] | 1133–1200 | 986–1022 | - | 3.4–11 | ||||
| Stress relief annealing [26,31,32] | 980–1115 | 1045–1054 | - | 10–12 | |||||
| Subtransus annealing [26,31] | 950–988 | 905–911 | - | 9.5–16 | |||||
| STA [32] | 781 ± 8 | - | - | 3.6 ± 0.6 | |||||
| WA-DED | As-built [18,27] | 820–847 | 710–746 | - | 7.2–12.2 | ||||
| Stress relief annealing [18,27] | 872–854 | 766–772 | - | 10.9–11.8 | |||||
| Subtransus annealing [18] | 810 ± 9.04 | 721 ± 16.4 | - | 11.5 ± 4.15 | |||||
| STA [18,27] | 918–1034 | 858–931 | - | 5.9–7.5 | |||||
| Wrought | As-received [33] | 1016–1074 | 965–1021 | - | 15 | ||||
| Subtransus annealing [34] | 926 ± 2 | 878 ± 4 | - | 20 ± 1 | |||||
| STA [33,35,36] | 1028–1120 | 925–1050 | - | 10–16.3 | |||||
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Gatina, S.; Stotskiy, A.; Gareev, A.; Ryzhkin, A.; Semenova, I.; Mamalat, A.; Klimova-Korsmik, O.; Zherebtsov, S.; Enikeev, N. Effect of Heat Treatment on the Microstructure and Mechanical Properties of Ti–6Al–4V Alloy Produced by L-PBF and PA-DED. Metals 2026, 16, 792. https://doi.org/10.3390/met16070792
Gatina S, Stotskiy A, Gareev A, Ryzhkin A, Semenova I, Mamalat A, Klimova-Korsmik O, Zherebtsov S, Enikeev N. Effect of Heat Treatment on the Microstructure and Mechanical Properties of Ti–6Al–4V Alloy Produced by L-PBF and PA-DED. Metals. 2026; 16(7):792. https://doi.org/10.3390/met16070792
Chicago/Turabian StyleGatina, Svetlana, Andrey Stotskiy, Alfiz Gareev, Alexander Ryzhkin, Irina Semenova, Alexey Mamalat, Olga Klimova-Korsmik, Sergey Zherebtsov, and Nariman Enikeev. 2026. "Effect of Heat Treatment on the Microstructure and Mechanical Properties of Ti–6Al–4V Alloy Produced by L-PBF and PA-DED" Metals 16, no. 7: 792. https://doi.org/10.3390/met16070792
APA StyleGatina, S., Stotskiy, A., Gareev, A., Ryzhkin, A., Semenova, I., Mamalat, A., Klimova-Korsmik, O., Zherebtsov, S., & Enikeev, N. (2026). Effect of Heat Treatment on the Microstructure and Mechanical Properties of Ti–6Al–4V Alloy Produced by L-PBF and PA-DED. Metals, 16(7), 792. https://doi.org/10.3390/met16070792

