In Bending processes (steel tool or pad forming) we create a tension-compression situation with refer to the Neutral Axis (N.A).

Regarding magnesium sheet, the mission should be to run the process at room or moderate temperature (below 200°C), depends on the bending radii.

Considering magnesium profiles or tubes: in this case the deformation regime can face non-homogenous conditions and the process is usually done at a relativly high temperature.
Therefore, a propoer tooling design might be the key.