316L stainless-steel 316LN 3D printing 5356-aluminum EN AW-7075 Technology: general issues Ti-6Al-4V WAAM additive manufacturing additive manufacturing (AM) bioactive layers biological origin hydroxyapatite cavity resonators cold metal transfer cold working cranial mesh implants direct energy deposition directed energy deposition electron backscattered diffraction method electron beam melting electron beam melting (EBM) electron microscopy filters grain selection heat treatments hot working injection molding laser-based powder bed fusion (L-PBF) magnesium mechanical properties