Precipitation and Distribution Behavior of In Situ-Formed TiB Whiskers in Ti64 Composites Fabricated by Selective Laser Melting

The precipitation and distribution behaviors of in situ-formed titanium boride whiskers (TiB) TiBw-reinforced Ti-6%Al-4%V (Ti64) composites fabricated from an elemental mixture Ti64 alloy powder TiB2 particles by selective laser melting were investigated. primary TiB strongly depends on B content. For a content less than 2 mass%, when the liquid → β-phase transformation occurred atoms discharged, B-enriched area formed around resulted generation their agglomeration at prior β-grain boundaries. When was over directly precipitated phase moved to molten pool boundary via Marangoni convection. As result, located along boundary. Furthermore, B-enrichment caused decrease liquidus temperature thus obstructed coarsening, as fine equiaxed α’-grains during transformation.