Development of novel titanium alloys for laser powder bed fusion
This work presented in this talk is part of a wider research programme dedicated to the understanding of the new metallurgy of light alloys produced by laser powder-bed fusion (L-PBF). This talk will focus on Ti-6Al-4V, the most widely used α + β titanium alloy. The current understanding of the microstructural evolution of Ti-6Al-4V during L-PBF will be reviewed first. Then two strategies to improve the microstructure and mechanical properties of this alloy are proposed. In the first instance, we propose a novel heat treatment that is capable to refine the columnar grain structure of Ti-6Al-4V. The heat treatment exploits the non-equilibrium microstructure found in the as-built L-PBF components to encourage recrystallization and a significant change in crystallographic texture. In the second approach, the influence of Fe on the microstructural development of Ti-6Al-4V is evaluated. By exploiting the cooling rates typical of L-PBF it will be shown how it is possible to obtain a refined metastable microstructure. In turn, this microstructure can be optimised by conventional heat treatments to obtain a desirable balance of strength-ductility. The characterisation techniques that are used include (high-temperature) EBSD, TEM and in-situ high energy synchrotron X-ray diffraction. The results are discussed with the support of relevant thermodynamic calculations based on the CALPHAD method. . Opportunities and challenges for the design of novel alloys for use in AM will also be discussed.
Dr. M. Simonelli
Nottingham Research Fellow, Faculty of Engineering
University of Nottingham
Jubilee Campus
Wollaton Road
Nottingham NG8 1BB
UK
| Phone | +44 115 8468441 |
| Dr. M. Simonelli | |
| Http | Dr. M. Simonelli |
| Centre for Additive Manufacturing, Nottingham University | |
| University of Nottingham |