Effect of build geometry on the β-grain structure and texture in additive manufacture of Ti6Al4V by selective electron beam melting

With titanium alloys, the solidification conditions in Additive Manufacturing (AM) frequently lead to coarse columnar β-grain structures. The effect of geometry on the variability in the grain structure and texture, seen in Ti6Al4V alloy components produced by Selective Electron Beam Melting (SEBM), has been investigated. Reconstruction of the primary β-phase, from α-phase EBSD data, has confirmed that in bulk sections where in-fill “hatching” is employed growth selection favours columnar grains aligned with an β direction normal to the deposited powder layers; this results in a coarse β-grain structure with a strong β fibre texture (up 8 x random) that can oscillate between a near random distribution around…

• EA
  Engineering and Physical Sciences Research Council

  Awards: EP/G022402/1, EP/H020047/1