Thermophysical and microstructural characterization of Ti-6Al-4V in powder and laser powder bed fusion-processed state within the global temperature field range
To pave the way for thermophysical modeling and further PBF-LB/M process optimization, the thermophysical properties of Ti-6Al-4V in powder and processed states were investigated using thermo-mechanical analysis, laser flash analysis, and differential scanning calorimetry. Microstructural characteri...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-05-01
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| Series: | Materials & Design |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0264127525002436 |
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| Summary: | To pave the way for thermophysical modeling and further PBF-LB/M process optimization, the thermophysical properties of Ti-6Al-4V in powder and processed states were investigated using thermo-mechanical analysis, laser flash analysis, and differential scanning calorimetry. Microstructural characterization using SEM, Vickers hardness testing, and XRD facilitated a novel interpretation of the results. The macroscopic density exhibited a linear relationship up to 880C∘, showing only a minor impact from microstructural effects. The evolution of α′ martensitic microstructure was analyzed by examining linear thermal expansion coefficients indicating direction dependency. During heating, the precipitation and stabilization of β provoke the formation and decomposition of the intermetallic phase, accompanied by a significant increase in hardness and an exothermic event. Additionally, the relaxation of residual stresses and transformation into the β phase determines the microstructural evolution. Thermal diffusivity of as-built Ti-6Al-4V propagates linearly up to 950C∘. For powder, HotDisk measurements corroborate laser flash data obtained up to 850C∘. Based on the LFA, the start of sintering is identified and attributed to a change in the heat transfer mechanism in AM powders. Specific heat capacity and effective thermal conductivity of AM Ti-6Al-4V are determined, highlighting the shortcomings of predicting AM powders' conductivity based on solid materials. |
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| ISSN: | 0264-1275 |