Transformation of cobalt gradient structure after resintering of DP cemented carbide

► Cobalt gradient structure changed from the initial sharp type to a gradual type. ► Hardness in the initial surface and intermediate zones was improved. ► Carbon distribution self-optimization (CDSO) was proposed. ► WC + β structure self-realization and property self-optimization were discussed. ► CDSO and residual compressive macrostress are responsible for the high property.