▎ 摘　　要

The current study applies towards investigate the sintering behavior, mechanical properties as well as stability of predesigned Co gradient of nano-laminated multi-layer graphene (MLG) reinforced WC-Co composites, highlighting the critical roles of MLG as exceptional toughening phase and superior cobalt gradient stability enhancement phase. During liquid phase sintering, the stability of predesigned cobalt gradient can be significantly enhanced via controlling MLG content. The three crucial cobalt gradient stability enhancing mechanisms are MLG preferential orientation, MLG inducing the generation of the liquid cobalt phase and MLG wrapping matrix grains. MLG intrinsic toughening mechanism i.e. MLG bending together with extrinsic toughening mechanisms such as MLG wrapping, interface debonding, MLG wall and network, MLG induced weak interface, MLG pullout, crack deflection, crack bridging and crack stopping is the major toughening mechanisms. Besides, stabilization of the predesigned Co-gradient and grain reinforcement are also the important contribution to the improved hardness to toughness relationship.