When Defects strengthen 3D-printed material

If you can't beat it join it or so the saying goes!

"... researchers found a counterintuitive way of improving 3D-printed metal alloys. By deliberately introducing more defects into the printing process, followed by a post-processing treatment that uses high temperature and high pressure to change the material’s microstructure, they turned the defects into assets, resulting in a stronger, more ductile metal product.
The technique could potentially be applied to any 3D-printed metal alloy and could be particularly effective for manufacturing products for biomedical and aerospace industries. ...
So we asked ourselves: What if we try to use those defects that are generally considered a limitation for additive manufacturing and turned them into the strengths of additive manufacturing? ..."

From the abstract:

"Rapid cooling rates and stochastic interactions between the heat source and feedstock in additive manufacturing (AM) result in strong anisotropy and process-induced defects deteriorating the tensile ductility and fatigue resistance of printed parts. We show that by deliberately introducing a high density of lack of fusion (LoF) defects ... followed by hot isostatic pressing (HIP), we can print Ti-6Al-4V with reduced texture and combinations of strength (TS=1.0 ± 3E-2 GPa) and ductility (εfailure=20 ± 1%) surpassing that of wrought, cast, forged, annealed, solution-treated and aged counterparts. ..."

When bad makes good: Defects strengthen 3D-printed material | Cornell Chronicle

Exploiting lack of fusion defects for microstructural engineering in additive manufacturing (no public access)