The invention discloses a billet making die for differential velocity cyclic
extrusion of a high performance
rare earth magnesium alloy. The billet making die for the differential velocity cyclic
extrusion of the high performance
rare earth magnesium alloy comprises an upper die
assembly, a "T"-shaped punch, a split concave die and a lower die
assembly. The split concave die comprises an upper concave die and a lower concave die. The upper concave die is provided with an upper rectangular die cavity and an upper half polygons expansion die cavity, the lower concave die is provided with a lowerrectangular die cavity and a
lower half polygons expansion die cavity, and the upper concave die and the lower concave die combine to form a polygons expansion die cavity. Differential velocity angles are arranged on both sides of the
lower half polygons expansion die cavity, and the height of the differential velocity angles on both sides is different. The lower die
assembly comprises a first lower template of a
solid body, a
gasket block and a second lower template with a through hole. The first lower template is used for fixing at the bottom of the lower concave die during upsetting, and the
gasket block blocks the lower rectangular die cavity. By changing the die cavity structures of the concave dies, the
metal flow state is changed, the shear deformation is introduced, the strain growth is realized, the deformation times are reduced, the
strain effect is improved, the production efficiency is improved, the
grain structure is refined, and the second phase structure is optimized.