Excessive porosity after liquid-phase sintering of elemental titanium powder blends

The liquid-phase sintering of binary titanium alloys using blended elemental powders has been explored. When silicon or nickel were mixed with titanium powder made by the hydride–dehydride route and sintered under vacuum, swelling and excessive porosity were observed if liquid was present and the relative density exceeded 90%. This is attributed to desorption of hydrogen into closed pores, which alters the pressure balance between the sample and the environment and opposes the sintering stress, causing expansion.