Coarse grained WC-9Co cemented carbides with 0-1.0% TaC(mass fraction) were fabricated by HIP-sintering and gas quenching. The effects of TaC on the microstructures and mechanical properties were investigated using sc...Coarse grained WC-9Co cemented carbides with 0-1.0% TaC(mass fraction) were fabricated by HIP-sintering and gas quenching. The effects of TaC on the microstructures and mechanical properties were investigated using scanning electron microscopy(SEM), energy dispersive X-ray analysis(EDS), X-ray diffractometry(XRD) and mechanical properties tests. The results show that the maximum values of hardness and strength are HV 1124 and 2466 MPa respectively when 0.4% TaC is added. When the content of TaC is more than 0.6%, the grain size of WC is no longer affected by the amount of TaC, and(W,Ta)C occurs as well. Moreover, the strength and fracture toughness increase and the(Ta+W) content decreases with the increase of TaC content. The dependence of(Ta+W) content on the mechanical properties indicates that(Ta+W) content in Co should be decreased as low as possible to improve the mechanical properties of coarse grained WC-TaC-9Co cemented carbides with the microstructure of WC+γ two phase regions.展开更多
The effects of preheating temperature and W powder size on the Self propagating High temperature Synthesis(SHS) of Ti W C system were studied. Preheated mixtures and the decrease of W powder size can accelerate the fo...The effects of preheating temperature and W powder size on the Self propagating High temperature Synthesis(SHS) of Ti W C system were studied. Preheated mixtures and the decrease of W powder size can accelerate the formation of (W,Ti)C powders. The uniphase (W,Ti)C (WC∶TiC=5∶5) powders with 0.32% free carbon were synthesized from Ti, W, C powders by SHS. The powder size of the product was 3～5 μm.展开更多
Eight comptexes (RC_5H_4)_2Ti(O_2CA_r)_2(R=H,CH_3;Ar= with 2 equiv.N_aO_2CA_r.The carboxytate ligands in the complexes coordinate to titan^um atom in monodentate mode.(CH_3C_5H_4)_2Ti(O_2CC_4H_3S-2)_2 has four-coordin...Eight comptexes (RC_5H_4)_2Ti(O_2CA_r)_2(R=H,CH_3;Ar= with 2 equiv.N_aO_2CA_r.The carboxytate ligands in the complexes coordinate to titan^um atom in monodentate mode.(CH_3C_5H_4)_2Ti(O_2CC_4H_3S-2)_2 has four-coordinate bent titanocene in which the thiophencarboxyaltes are a monodeotate ligand(Ti-0=1.981(8)A,1.926(3)A;) 0-Ti-0:91.6(8)~ ; Ti-C:2.333-2.440A).展开更多
基金Project(2013zzts025)supported by the Fundamental Research Funds for the Central Universities of China
文摘Coarse grained WC-9Co cemented carbides with 0-1.0% TaC(mass fraction) were fabricated by HIP-sintering and gas quenching. The effects of TaC on the microstructures and mechanical properties were investigated using scanning electron microscopy(SEM), energy dispersive X-ray analysis(EDS), X-ray diffractometry(XRD) and mechanical properties tests. The results show that the maximum values of hardness and strength are HV 1124 and 2466 MPa respectively when 0.4% TaC is added. When the content of TaC is more than 0.6%, the grain size of WC is no longer affected by the amount of TaC, and(W,Ta)C occurs as well. Moreover, the strength and fracture toughness increase and the(Ta+W) content decreases with the increase of TaC content. The dependence of(Ta+W) content on the mechanical properties indicates that(Ta+W) content in Co should be decreased as low as possible to improve the mechanical properties of coarse grained WC-TaC-9Co cemented carbides with the microstructure of WC+γ two phase regions.
文摘The effects of preheating temperature and W powder size on the Self propagating High temperature Synthesis(SHS) of Ti W C system were studied. Preheated mixtures and the decrease of W powder size can accelerate the formation of (W,Ti)C powders. The uniphase (W,Ti)C (WC∶TiC=5∶5) powders with 0.32% free carbon were synthesized from Ti, W, C powders by SHS. The powder size of the product was 3～5 μm.
文摘Eight comptexes (RC_5H_4)_2Ti(O_2CA_r)_2(R=H,CH_3;Ar= with 2 equiv.N_aO_2CA_r.The carboxytate ligands in the complexes coordinate to titan^um atom in monodentate mode.(CH_3C_5H_4)_2Ti(O_2CC_4H_3S-2)_2 has four-coordinate bent titanocene in which the thiophencarboxyaltes are a monodeotate ligand(Ti-0=1.981(8)A,1.926(3)A;) 0-Ti-0:91.6(8)~ ; Ti-C:2.333-2.440A).
