The aim of this study is to optimize the economic net-shape forming of titanium and titanium alloys for the biomedical application. The alpha-case formation reaction between titanium, and Al2O3, ZrO2, CaO stabilized ZrO2 and ZrSiO4 mold were examined in a plasma arc melting furnace. Regardless of the thermodynamic approach, α-case formation reactions still remain to be eliminated with the complex chemical milling processes. The reason why the α-case generated cannot be explained by the conventional α-case formation mechanism. However, from the experimental results and thermodynamic consideration, it can be confirmed that the α-case is formed not only by interstitial oxygen atoms but also by substitutional metal atoms dissolved from mold materials. Based on the interstitial and substitutional α-case formation mechanism, α-case controlled net-shape forming of titanium and titanium alloys can be possible for the biomedical application.