Effects of composite binder phase on microstructure and mechanical properties of ultrafine‐grained cemented carbides

Abstract

In order to develop a new high-performance binder phase, four different alloys Co-Ni-Fe, Co-Ni-Cr, Co-Ni-Nb, and AlCoCrNiNb 0.5 were used as a binder in cemented carbides. The room-temperature mechanical properties and high-temperature flexural strength of cemented carbides were studied. The results show that the optimal mechanical properties for the WC-8(Co-Ni-Fe, Co-Ni-Cr, Co-Ni-Nb, and AlCoCrNiNb 0.5) can be obtained at the sintering temperatures of 1200°C, 1350°C, 1350°C, and 1300°C, respectively. Compared with cemented carbides with Co as binder phase, the hardness of the four kinds of alloys is increased, the WC grain size becomes finer, but the fracture toughness is slightly decreased. When the temperature is under 600°C, there is no visible oxidation of the four kinds of cemented carbides, and their bending strengths are basically not reduced. When the temperature increased from 600°C to 900°C, the WC-8(Co-Ni-Nb) and WC-8(Co-Ni-Fe) samples present the better high-temperature bending resistance compared with the WC-8(Co-Ni-Cr) and WC-8AlCoCrNiNb 0.5 samples, with respective decrease in bending strength of 11.7% and 7.3%. K E Y W O R D S carbides, composite binder phase, mechanical properties, spark plasma sintering How to cite this article: Yu B, Wang Z, Sun N, et al. Effects of composite binder phase on microstructure and mechanical properties of ultrafine-grained cemented carbides.

Ultrafine WC–Co cemented carbide end mills prepared by spark plasma sintering and wear mechanism in milling of AISI H13

“…[16][17][18][19] Compared to fine and submicron cemented carbides (.5-1.3 μm), ultrafine cemented carbides demonstrate superior hardness and wear resistance. [20][21][22][23][24] Bonache et al 25 compared the mechanical properties of WC-12Co cemented carbides prepared using spark plasma and vacuum sintering. The cemented carbide prepared by vacuum sintering had a grain size of 747 nm and a hardness of 1500 kg/mm 2 , while that prepared by spark plasma sintering had a grain size of 216 nm and a hardness of 1830 kg/mm 2 .…”

“…Ultrafine cemented carbides are a type of hard material that can be produced using rapid sintering technology and are composed of cobalt (Co) and ultrafine tungsten carbide (WC) with a grain size of .2 to .5 μm 16–19 . Compared to fine and submicron cemented carbides (.5–1.3 μm), ultrafine cemented carbides demonstrate superior hardness and wear resistance 20–24 . Bonache et al 25 .…”

Performance of B4C/CeB6 composites fabricated via hot pressing under different processes

“…In sintering process, rare earth oxides form liquid phase, fill the pores among the grains through capillary action, and meanwhile take the effect of grain refining, improving the densification and strengthening the materials. 15 In addition, the thermal expansion coefficients of earth oxides are different from that of B 4 C, thus using rare earth oxides as sintering additives can improve the mechanical properties of B 4 C ceramic. 16 Studies show that using the common rare earth oxides such as Y 2 O 3 , CeO 2 , La 2 O 3 , Nd 2 O 3 , Dy 2 O 3 , Eu 2 O 3 , and Sm 2 O 3 as sintering additives can greatly improve the sintering performance of B 4 C ceramics.…”

“…Rare earth oxide is a good choice for improving the properties of hybrid composites due to its unique properties. In sintering process, rare earth oxides form liquid phase, fill the pores among the grains through capillary action, and meanwhile take the effect of grain refining, improving the densification and strengthening the materials 15 . In addition, the thermal expansion coefficients of earth oxides are different from that of B 4 C, thus using rare earth oxides as sintering additives can improve the mechanical properties of B 4 C ceramic 16 .…”