The effects of ultrafine WC(WC_(UF),0.5μm) or W(1μm) and C(0.3μm)(W+C)_(UF) additives on the densification,microstructure and mechanical properties of coarse-grained cemented carbides were compared systematically.O...The effects of ultrafine WC(WC_(UF),0.5μm) or W(1μm) and C(0.3μm)(W+C)_(UF) additives on the densification,microstructure and mechanical properties of coarse-grained cemented carbides were compared systematically.Overall,the cemented carbides with WC_(UF)/(W+C)_(UF) additives are almost fully densification to be higher than 99%,and the average grain size is kept above 2.8μm.The WC_(UF) additive assists grains to(truncated)trigonal prism shape by two dimensional(2D) growth,whereas the(W+C)_(UF) additive assists grains to rounded shape by three dimensional(3D) growth,lowers WC contiguity and increases face-centered-cubic Co.The hardness and bending strength of(75WC_(C)-15WC_(UF))-10Co are 86.6 HRA and 2 272 MPa,respectively,both higher than those of(75WC_(C)-15(W+C)_(UF))-10Co,which could be ascribed to the enhanced densification and unblemished grains.However,the fracture toughness of the(75WC_(C)-15(W+C)_(UF))-10Co is 23.5 MPa·m^(1/2),higher than that of the(75WC_(C)-15WC_(UF))-10Co due to the uniform WC-Co structure and flexible binder phase.展开更多
The nanocomposite WC-Co powders were prepared through planetary ball milling method.Effects of grain growth inhibitor addition and the vacuum sintering parameters on the microstructure and properties of ultrafine WC-1...The nanocomposite WC-Co powders were prepared through planetary ball milling method.Effects of grain growth inhibitor addition and the vacuum sintering parameters on the microstructure and properties of ultrafine WC-10Co cemented carbides were investigated using X-ray diffractometer,scanning electron microscope and mechanical property tester.The results show that VC and NbC additions can refine the WC grains,decrease the volume fraction of Co3W3C phase in ultrafine WC-10Co cemented carbides,and increase the hardness and fracture toughness of the base alloys.After sintering for 60 min at 1 400℃,the average grain size and hardness of ultrafine-grained WC-10Co-1VC cemented carbide are 470 nm and HRA 91.5,respectively.The fracture toughness of cemented carbide WC-10Co-1NbC alloy is over 7 MN·m -3/2 .展开更多
HVOF thermal spraying tests were carried out for thermal spraying the coatings with two kinds of cermet powders,which are microstructured Sulzer Metco Diamalloy 2004 WC-12%Co powders and nanostructured WC-12%Co powder...HVOF thermal spraying tests were carried out for thermal spraying the coatings with two kinds of cermet powders,which are microstructured Sulzer Metco Diamalloy 2004 WC-12%Co powders and nanostructured WC-12%Co powders.The microstructures of the as-prepared WC-12%Co coatings were then characterized by using XRD analyzer and SEM.The mechanical properties of the two coatings were evaluated by microhardness test,bend test,cup test,tensile test and abrasive wear test.The results showed that the mechanical properties of WC-12%Co coatings sprayed with nanostructured WC-12%Co powder is higher than that of coatings sprayed with microstructured WC-12%Co powders,and the reasons were discussed.展开更多
基金Funded by the Technology Innovation Leading Program of Shaanxi(No.2022QFY08-02)。
文摘The effects of ultrafine WC(WC_(UF),0.5μm) or W(1μm) and C(0.3μm)(W+C)_(UF) additives on the densification,microstructure and mechanical properties of coarse-grained cemented carbides were compared systematically.Overall,the cemented carbides with WC_(UF)/(W+C)_(UF) additives are almost fully densification to be higher than 99%,and the average grain size is kept above 2.8μm.The WC_(UF) additive assists grains to(truncated)trigonal prism shape by two dimensional(2D) growth,whereas the(W+C)_(UF) additive assists grains to rounded shape by three dimensional(3D) growth,lowers WC contiguity and increases face-centered-cubic Co.The hardness and bending strength of(75WC_(C)-15WC_(UF))-10Co are 86.6 HRA and 2 272 MPa,respectively,both higher than those of(75WC_(C)-15(W+C)_(UF))-10Co,which could be ascribed to the enhanced densification and unblemished grains.However,the fracture toughness of the(75WC_(C)-15(W+C)_(UF))-10Co is 23.5 MPa·m^(1/2),higher than that of the(75WC_(C)-15WC_(UF))-10Co due to the uniform WC-Co structure and flexible binder phase.
基金Project(50823006)supported by the National Natural Science Foundation of ChinaProject(200801348)supported by China Postdoctoral Science FoundationProject(50721003)supported by Innovative Research Groups of the National Natural Science Foundation of China
文摘The nanocomposite WC-Co powders were prepared through planetary ball milling method.Effects of grain growth inhibitor addition and the vacuum sintering parameters on the microstructure and properties of ultrafine WC-10Co cemented carbides were investigated using X-ray diffractometer,scanning electron microscope and mechanical property tester.The results show that VC and NbC additions can refine the WC grains,decrease the volume fraction of Co3W3C phase in ultrafine WC-10Co cemented carbides,and increase the hardness and fracture toughness of the base alloys.After sintering for 60 min at 1 400℃,the average grain size and hardness of ultrafine-grained WC-10Co-1VC cemented carbide are 470 nm and HRA 91.5,respectively.The fracture toughness of cemented carbide WC-10Co-1NbC alloy is over 7 MN·m -3/2 .
文摘HVOF thermal spraying tests were carried out for thermal spraying the coatings with two kinds of cermet powders,which are microstructured Sulzer Metco Diamalloy 2004 WC-12%Co powders and nanostructured WC-12%Co powders.The microstructures of the as-prepared WC-12%Co coatings were then characterized by using XRD analyzer and SEM.The mechanical properties of the two coatings were evaluated by microhardness test,bend test,cup test,tensile test and abrasive wear test.The results showed that the mechanical properties of WC-12%Co coatings sprayed with nanostructured WC-12%Co powder is higher than that of coatings sprayed with microstructured WC-12%Co powders,and the reasons were discussed.
基金National Natural Science Foundation of China(51405326,51575375)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2014122)
