Laser-aided manufacturing technologies; their application to the near-net shape forming of high-strength titanium alloy

A number of blocks of the high-strength alpha–beta titanium alloy Ti–6Al–2Sn–4Zr–6Mo (Ti-6246) were manufactured using direct laser fabrication. Two processing methods were investigated; one of which used a high-power (18 kW) CO2 laser, the other using a (4 kW) Nd-YAG laser. Following manufacture, the blocks were sectioned and mechanically tested to compare the properties of material produced using the two processes. The mechanical assessment involved a combination of room temperature tensile testing and fracture toughness measurements. The results revealed that the Ti-6246 produced using both processing routes exhibited a low ductility (<3% elongation). The fracture toughness figures were, however, acceptable. The low ductility was thought to be linked to the presence of a large transformed beta grain size together with the presence of grain boundary alpha.