Journal
ADDITIVE MANUFACTURING
Volume 20, Issue -, Pages 11-22Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.addma.2017.12.010
Keywords
Additive manufacturing; Laser polishing; Titanium; Microstructure; Residual stresses
Funding
- UK Engineering and Physical Sciences Research Council through the Centre for Innovative Manufacturing in Laser-Based Production Processes [EP/K030884/1]
- SPI Lasers UK Ltd
- Renishaw plc
- EPSRC [EP/K030884/1] Funding Source: UKRI
Ask authors/readers for more resources
Laser polishing (LP) is an emerging technique with the potential to be used for post-build, or in-situ, precision smoothing of rough, fatigue-initiation prone, surfaces of additive manufactured (AM) components. LP uses a laser to re-melt a thin surface layer and smooths the surface by exploiting surface tension effects in the melt pool. However, rapid re-solidification of the melted surface layer and the associated substrate thermal exposure can significantly modify the subsurface material. This study has used an electron beam melted (EBM)Ti6Al4V component, representing the worst case scenario in terms of roughness for a powder bed process, as an example to investigate these issues and evaluate the capability of the LP technique for improving the surface quality of AM parts. Experiments have shown that the surface roughness can be reduced to below Sa = 0.51 mu m, which is comparable to a CNC machined surface, and high stress concentrating defects inherited from the AM process were removed by LP. However, the remelted layer underwent a change in texture, grain structure, and a martensitic transformation, which was subsequently tempered in-situ by repeated beam rastering and resulted in a small increase in subsurface hardness. In addition, a high level of near-surface tensile residual stresses was generated by the process, although they could be relaxed to near zero by a standard stress relief heat treatment. (C) 2017 Published by Elsevier B.V.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available