Effects Of Sintering Temperature On Micostructure And Properties Of Ultrafine WC-TiC-TaC-Co Cemented Carbides

This paper studies the ultrafine WC-TiC-TaC-Co cemented carbides.The specimens were prepared by rubber technology.Density,TRS,hardness and Hc of the samplers was measured by Mettler-Toledo,electronic testing machine,Wien hardmeter and coercive force meter,respectively. The tesiting results show that the density of ultrafine WC-1.0～2.0%TiC-1.0～2.0%TaC-6.0～10.0%Co cemented carbides change slightly,the TRS of which first decreases and then increases,the hardness and Hc of which decreases continuously asthe sintering temperature increases.Some free graphites and plently of pores occure in the ultrfine WC-1.0～2.0%TiC-1.0～2.0%TaC-6.0～10.0%Co cemented carbides by Zeiss optical microscope SEM-EDS and XRD.The reasons of which is that the contents of total carbon in the green compacts is higher than of the nomal structure of WC-Co and long time drying of green compacts after granulating.The numbers of pores and the contents of(W,Ti)C first increases and them decreases as the sintering temperature increases.Disscussing the effects of the sintering temperature on microstructural development and mechanical properties of ultrafine WC-TiC-TaC-Co cemented carbides and correlation of the contents of inhibitors and mechanical properties of ultrafine cemented carbides,the authors makes some conclusions as follows:(1)When the sintering temperature below the 1435℃,the TRS of ultrafine WC-1.0～2.0%TiC-1.0～2.0%TaC-6.0～10.0%Co cemented carbides decreases as the sintering temperature increases,when the sintering temperature above the 1435℃,the TRS of ultrafine WC-1.0～2.0%TiC-1.0～2.0%TaC-6.0～10.0%Co cemented carbides increases with the sintering temperature increasing.(2)The hardness of ultrafine WC-1.0～2.0%TiC-1.0～2.0%TaC-6.0～10.0%Co cemented carbides first decreases slowly and then fast with the sintering temperature increasing.(3)When sintered temperature at 1400℃for one hour,the mechanical properties of ultrafine WC-1.0～2.0%TiC-1.0～2.0%TaC-6.0～10.0%Co cemented carbides is optimization.(4)3D-figure optimizational design supplies the efficient method for studying the correlation of the contents of inhibitors and mechanical properties of WC-Co cemented carbides,by which we can easily find out the majorized contents of inhibitors for the optimizational mechanical properties of WC-Co cemented carbides...