Hot forging of cast magnesium alloy TX31 using semi-closed die and its finite element simulation

Magnesium alloys based on Mg-Sn-Ca system have shown improved corrosion and creep properties. In this type of alloys,Sn forms a solid solution with Mg that improves the corrosion resistance while Ca forms thermally stable intermetallic phases in the matrix enhancing the creep resistance. The Sn to Ca ratio is an important variable in deciding the type of intermetallic phases that form in the microstructure. In Mg-3Sn-1Ca alloy (TX31), a single intermetallic phase CaMgSnforms, which is responsible for its improved creep strength.With a view to evaluate its forgeability, isothermal forging experiments of TX31 were conducted on a hydraulic press in the temperature range of 350°C to 500°C and at speeds of 0.01 mm s^-1to 10 mm s^-1 using a semiclosed die. Finite-element (FE) simulation of the forging process was also conducted using the software DEFORM 2D to obtain the local variations of strain and strain rate. The effectivestrain values are below2.4 in the forged components and the forging loads predicted using FE simulation correlated well with the experimental data for all the forging conditions. The microstructures of the forgings show that CaMgSn phase is well distributed in the matrix which exhibited dynamically recrystallized microstructure as predicted by the processing map.