The most familiar route to produce feedstock billets for aluminum thixocasting is by magnetohydrodynamic (MHD). This process cannot be used currently for magnesium alloys for safety measures and this is the reason why we have developed and tested three processes for elaboration of real thixotropic magnesium billets. To inject these billets we have finalized a new thixoforming process called THIXOMAG(TM) without gas protection avoiding global warming and with any risk of explosion, adaptable to a conventional cold chamber pressure die casting machine to avoid expensive and complicated solutions. This device is suited both for magnesium and aluminum alloys with the same apparatus and characterized by a rapid. and homogeneous induction reheating of billets in the semi-solid state before injection of casting parts. Two different processes are practiced: partisans of semi-solid die casting with 40 % to 55 % of solid phase associated to laminar filling for thick and strong casting parts to compete with forging and partisans of semi-liquid operate between 5 % and 20 % associated to turbulent filling for thinner casting parts. Therefore it is a question of choice. The THIXOMAGT(TM) process turns this situation to best account comes to the choice of semi-solid way just as well aluminum alloys as magnesium alloys to obtain laminar-filling shown also by mold flow software. The THIXOMAG(TM) process is closely linked with high pressure die casting in order to obtain semi-solid structure that displays an important increase of strain after heat treatment and rise of AZ91D Young's modulus correlated with and homogeneous two phases structure with thin intermetallic lamellas. Corrosion resistance is also increased in comparison of conventional cast parts obtained by liquid die-casting. Cycle time of 27 s with three induction coils. Wall thickness parts from one and half millimeter to several centimeters without porosity. All these advantages are well suitable for net shape magnesium and aluminum parts necessary for automotive market.