Method of strengthening binder metal phase of sintered body

Abstract

Spherical shaped ejection particles are ejected against a surface of a sintered body including hard particles and a binder metal phase bonding the hard particles together, with a compressed gas at an ejection pressure of from 0.2 MPa to 0.6 MPa or at an ejection velocity of from 80 m/s to 200 m/s and the spherical ejection particles having a hardness not less than the hardness of the binder metal phase and that is a hardness of 1000 HV or less and being particles having an average particle diameter from 20 μm to 149 μm. Thus, plastic deformation resulting from such impact and the instantaneous temperature rise and cooling occurring at the impact sites micronizes the structure of the binder metal phase, causes a change to a dense structure, and imparts compressive residual stress thereto. This results in strengthening, and enables prevention of brittle fracture in the sintered body.

Dependencies are inferred from the claim text.