Ti-6Al-(sub4)V produced by laser powder bed fusion can achieve mechanical properties similar to its wrought counterpart if an appropriate post-process heat treatment is applied. The response of the material to post-process heat treatment depends on the prior-beta grain size in the as-built condition. The current article illustrates that a reduction in hatch distance can cause coarsening of prior-beta grains due to retained heat that reduces the cooling rate. On the other hand, an increase in scan speed refines prior-beta grains. Unfortunately, an increase in scan speed has to be accompanied by a reduction in hatch distance to prevent an increase in porosity and the potential grain refinement is then cancelled out. The use of a faster scan speed in combination with a smaller hatch distance significantly improves roughness of the top surface. EBSD in combination with reconstruction of prior-beta grains is an effective technique to quantify prior-beta grain size. Furthermore, the use of Rosenthal’s equations allows quick calculation of cooling rate that can be used to predict the dependence of prior-beta grain size on process parameters.
Reference:
Louw, D.F. & Pistorius, P.G.H. 2019. The effect of scan speed and hatch distance on prior-beta grain size in laser powder bed fused Ti-6Al-4V. The International Journal of Advanced Manufacturing Technology, Vol. 103(5-8): p. 2277-2286. https://doi.org/10.1007/s00170-019-03719-w
Louw, D. F., & Pistorius, P. (2019). The effect of scan speed and hatch distance on prior-beta grain size in laser powder bed fused Ti-6Al-4V. http://hdl.handle.net/10204/11093
Louw, Daniel F, and PGH Pistorius "The effect of scan speed and hatch distance on prior-beta grain size in laser powder bed fused Ti-6Al-4V." (2019) http://hdl.handle.net/10204/11093
Louw DF, Pistorius P. The effect of scan speed and hatch distance on prior-beta grain size in laser powder bed fused Ti-6Al-4V. 2019; http://hdl.handle.net/10204/11093.
Copyright: 2019 Springer Due to copyright restrictions, the attached PDF file only contains the abstract version of the full-text item. For access to the full-text item, please consult the publisher's website. The definitive version of the work is published in The International Journal of Advanced Manufacturing Technology (2019) 103: 2277. A free full-text non-print version of the published item can be viewed at https://rdcu.be/bOPeS