SPS Preparation Process And Cutting Performance Of New Binder Phase Cemented Carbide

Aiming at the disadvantages of poor high-temperature performance of traditional Co binder phase,this paper uses four alloys of Co-Ni-Fe,Co-Ni-Cr,Co-Ni-Nb and Al Co Cr Ni Nb0.5as the binder phase of cemented carbide.Spark plasma sintering technology has prepared high-performance composite cemented carbide tools and studied their high-temperature performance.At the same time,the pressure sintering process for preparing three-dimensional groove-shaped cutting tools was investigated.Finally,the cutting performance of three-dimensional groove-shaped cutting tools and flat cutting tools was compared.Based on spark plasma sintering technology,the effects of composite binder phase types and sintering temperature on the microstructure and mechanical properties of cemented carbide are studied.The results show that WC-8(Co-Ni-Fe),WC-8(Co-Ni-Cr),WC-8(Co-Ni-Nb),WC-8Al Co Cr Ni Nb0.5 at 1200,1350,1350 and 1300?to obtain the best room temperature mechanical properties.Among them,the comprehensive room temperature performance of WC-8(Co-Ni-Fe)is the best.Its density,hardness and fracture toughness is 99.6%,21.36 GPa and 11.24 MPa·m^1/2.In addition,compared with the Co binder phase cemented carbide,the average size of the four composite binder phase cemented carbides has been reduced from 400nm to 285,280,336 and 340 nm,respectively.The high temperature oxidation resistance and high temperature flexural strength of the composite binder phase cemented carbide are studied.Studies have shown that the oxide film formed by the oxidation of the four binder phases all has the effect of hindering the oxidation of the substrate,and the cemented carbide with Co-Ni-Fe and Co-Ni-Nb as the binder phase has the best oxidation resistance.When the ambient temperature is increased from 600°C to900°C,the flexural strength of WC-8(Co-Ni-Nb)and WC-8(Co-Ni-Fe)decrease slightly,only11.7%and 7.3%,respectively.Based on spark plasma pressure sintering,a method for preparing three-dimensional groove tools by pressing landfill powder is proposed.Studies have shown that with c BN powder as the landfill powder,the landfill powder is easily separated from the matrix after sintering,and there is no obvious structural deformation of the tool surface structure.The best pressing process for cemented carbide special-shaped tools is pressing pressure 100 MPa,powder embedding amount 0.8 g,holding pressure time 3 min.The relative density,Vickers hardness and fracture toughness of the tools are 99.48%,21.02 GPa and 11.24 MPa·m^1/2,respectively.The cutting performance of ultra-fine cemented carbide tools for dry cutting of titanium alloys was studied.The study found that the WC-8(Co-Ni-Fe)tool with a rake angle of 10°has the highest cutting life of 4000 m,and the commercial YG8 tool has the lowest cutting life of2500 m.It shows that the positive rake angle special-shaped tool prepared in this paper can improve the cutting life of cemented carbide tools.