Plastic deformation behavior during high-pressure torsion (HPT) was analyzed by the finite element method in order to investigate heterogeneous deformation in HPT-processed disks. The effective strain and strain rate developed increase from the center to the edge of the HPT-processed disk; however, they decrease to zero at the surface corner of the disk due to the vertical wall constraint under high pressure, resulting in a stagnant region termed the “dead metal zone”.