Forming die of Mg-Gd-Y-Zn-Zr magnesium alloy bidirectional expansion equal channel extrusion blank forming

The invention discloses a forming die of Mg-Gd-Y-Zn-Zr magnesium alloy bidirectional expansion equal channel extrusion blank forming. The forming die comprises an upper die seat, a male die and a female die, wherein the male die is a cylinder and is vertically installed on the upper die seat; the female die is arranged below the male die, is of an inverted "T" shape and is formed by communicatinga vertical cavity and a horizontal cavity with the same diameter; in addition, a spherical cabin is formed in the intersection part of the vertical cavity and the horizontal cavity, small circular beads are respectively arranged in the joint of the spherical cabin and the vertical cavity and the joint of the spherical cabin and the horizontal cavity, and the vertical cavity is used for accessing the male die. A bidirectional equal channel extrusion structure formed by the vertical cavity and the horizontal cavity is adopted, the spherical cabin is arranged in the channel joint, the compound superposition of the shear deformation in a cavity corner and the heading extrusion deformation in the spherical cabin during a material extrusion process is realized, accumulated plastic deformation process of a material is reached, refinement of a microstructure of a Mg-Gd-Y-Zn-Zr magnesium alloy blank is finally realized, and the mechanical property of an alloy is promoted.