Inducing stable a + ß microstructures during selective laser melting of Ti-6Al-4V using intensified intrinsic heat treatments
Selective laser melting is a promising powder-bed-based additive manufacturing technique for titanium alloys: near net-shaped metallic components can be produced with high resource-efficiency and cost savings. For the most commercialized titanium alloy, namely Ti-6Al-4V, the complicated thermal prof...
| Autores: | , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/387369 |
| Acceso en línea: | https://hdl.handle.net/2117/387369 https://dx.doi.org/10.3390/ma10030268 |
| Access Level: | acceso abierto |
| Palabra clave: | Titanium alloys Additive manufacturing Metals Selective laser melting Intrinsic heat treatment Metastable phases Phase transformations Martensite decomposition Element partitioning High energy synchrotron X-ray diffraction Synchrotron holographic X-ray computed tomography Titani -- Aliatges Fabricació additiva Metalls Àrees temàtiques de la UPC::Enginyeria mecànica |
| Sumario: | Selective laser melting is a promising powder-bed-based additive manufacturing technique for titanium alloys: near net-shaped metallic components can be produced with high resource-efficiency and cost savings. For the most commercialized titanium alloy, namely Ti-6Al-4V, the complicated thermal profile of selective laser melting manufacturing (sharp cycles of steep heating and cooling rates) usually hinders manufacturing of components in a one-step process owing to the formation of brittle martensitic microstructures unsuitable for structural applications. In this work, an intensified intrinsic heat treatment is applied during selective laser melting of Ti-6Al-4V powder using a scanning strategy that combines porosity-optimized processing with a very tight hatch distance. Extensive martensite decomposition providing a uniform, fine lamellar a + ß microstructure is obtained along the building direction. Moreover, structural evidence of the formation of the intermetallic a2-Ti3Al phase is provided. Variations in the lattice parameter of ß serve as an indicator of the microstructural degree of stabilization. Interconnected 3D networks of ß are generated in regions highly affected by the intensified intrinsic heat treatment applied. The results obtained reflect a contribution towards simultaneous selective laser melting-manufacturing and heat treatment for fabrication of Ti-6Al-4V parts. |
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