Effectiveness of residual stress and pores on the β-grain refinement in L-PBF Ti6Al4V processed with hot isostatic pressing
The present study examines the effect of HIP (Hot Isostatic Pressing) treatment above the β-transus temperature on porosity reduction and its effect on the transition from columnar to equiaxed prior β-grains in L-PBF (Laser Powder Bed Fusion) Ti6Al4V. HIP treatment was conducted at a holding tempera...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-07-01
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| Series: | Additive Manufacturing Letters |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2772369025000258 |
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| Summary: | The present study examines the effect of HIP (Hot Isostatic Pressing) treatment above the β-transus temperature on porosity reduction and its effect on the transition from columnar to equiaxed prior β-grains in L-PBF (Laser Powder Bed Fusion) Ti6Al4V. HIP treatment was conducted at a holding temperature of 1050 °C and a pressure of 120 MPa for 2 h on the L-PBF Ti6Al4V samples, which were deposited with four different scanning speeds of 300 mm/s, 400 mm/s, 650 mm/s, and 1100 mm/s, while keeping the other deposition parameters constant. The sample with the higher scanning speed (1100 mm/s) exhibits the highest area fraction of lack-of-fusion defects, leading to more pronounced equiaxed β-grain refinement and texture weakening compared to the sample that has the lowest scanning speed (300 mm/s) and negligible lack-of-fusion defect. During the HIP treatment, the local stresses around the sharp tips of the defects, along with the inherent residual stresses in the as-built samples, contribute to the dynamic recrystallization below and above the β-transus temperature. |
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| ISSN: | 2772-3690 |