The interaction between the face coat material of a mould and the titanium alloy will cause oxygen penetration during the casting and solidification process, resulting in the formation of an alpha-case interaction layer at the metal surface that influences the mechanical properties of the cast components. In this study, the influence of alpha-case thickness and loading positions in a Ti-6Al-4V (Ti64) alloy on metal hardness, impact properties and bending strength was investigated. The results showed that the metal surface alpha-case consisted of many coarse a laths which has a higher hardness than metal matrix. The mechanical properties of the alloy are influenced by the alpha-case. The alloy bending strength was observed to have changed linearly with the thickness of sample. (C) 2016 Elsevier B.V. All rights reserved.