To improve the strength of a material without changing the density, grain refinement strengthening is preferred. Grain refinement can be attained through various severe plastic deformation (SPD) techniques, such as accumulative roll-bonding (ARB), accumulative channel-die compression bonding (ACCB), and multi-directional forging (MULTIDIRECTIONAL FORGING) [15–18]. As Mg–Li-base alloys generally have poor resistance to corro sion, SPD techniques that bond materials, such as ARB, are not prefer able for the structure control of these alloys. On the other hand, MULTIDIRECTIONAL FORGING does not require the bonding of materials. In particular, MULTIDIRECTIONAL FORGING in a channel die (MULTIDIRECTIONAL FORGINGC) is attracting attention as a superior SPD technique because it is capable of introducing a larger equivalent strain, as compared to MULTIDIRECTIONAL FORGING, and does not require material bonding [19–21].