Synthesis of alloy Ti-6Al-4V with low residual porosity by a powder metallurgy method

The possibility of producing titanium alloy Ti-6Al-4V with minimal residual porosity from mixtures of elemental powders by the method of pressing and sintering without hot deformation during or after sintering was investigated. Various powder mixtures based on titanium and titanium hydride with alloying additions of either elemental powders having different particle sizes, or master alloys, were studied. It was shown that the synthesis of Ti-6Al-4V from mixtures of titanium hydride and master alloys is optimal with respect to the attainment of high relative density. In this case the sintered material has density up to 99%, homogeneous microstructure with relatively small (100-120 mum) beta-phase grains, and a low concentration of impurities, in particular oxygen, which provide a high level of mechanical properties (sigma(ten) = 970 MPa, delta = 6%).