Effects of Carbon Addition on Microstructures and Mechanical Properties of Binderless Tungsten Carbide

Nino, Akihiro; Takahashi, Kensuke; Sugiyama, Shigeaki; Taimatsu, Hitoshi

doi:10.2320/matertrans.m2012148

Cited by 45 publications

(30 citation statements)

References 23 publications

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“…The thermal conductivity of sintered WC samples without carbon addition was around 100 W/(m deg), whereas that of obtained WC specimens with carbon addition was close to 200 W/(m deg). However, excessive carbon addition can easily lead to the abnormal grain growth (AGG) of WC as well as the formation of graphite phase inducing cavities and pores in the sintered products [16,[35][36][37][38] preventing the full densification, implying that strictly controlling carbon content is essential in the design and fabrication of BTC.…”

Section: Mixed Carbon Contentmentioning

confidence: 99%

A Review on Binderless Tungsten Carbide: Development and Application

et al. 2019

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HIGHLIGHTS• Establish processing-composition-microstructure-property relationships governing binderless tungsten carbide (BTC).• Highlight the densification improving strategies and toughening methods for BTC.• Provide key challenges as well as the outlook for superior peformance associated with BTC.ABSTRACT WC-Co alloys have enjoyed great practical significance owing to their excellent properties during the past decades. Despite the advantages, however, recently there have been concerns about the challenges associated with the use of Co, i.e. price instability, toxicity and properties degeneration, which necessitates the fabrication of binderless tungsten carbide (BTC). On the other hand, BTC or BTC composites, none of them, to date has been commercialized and produced on an industrial scale, but only used to a limited extent for specialized applications, such as mechanical seals undergoing high burthen as well as high temperature electrical contacts. There are two challenges in developing BTC: fully densifying the sintered body together with achieving a high toughness. Thus, this review applies towards comprehensively summarize the current knowledge of sintering behavior, microstructure, and mechanical properties of BTC, highlighting the densification improving strategies as well as toughening methods, so as to provide reference for those who would like to enhance the performance of BTC with better reliability advancing them to further wide applications and prepare the material in a way that is environment friendly, harmless to human health and low in production cost. This paper shows that the fabrication of highly dense and high-performance BTC is economically and technically feasible. The properties of BTC can be tailored by judiciously selecting the chemical composition coupled with taking into careful account the effects of processing techniques and parameters.

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Section: Mixed Carbon Contentmentioning

confidence: 99%

A Review on Binderless Tungsten Carbide: Development and Application

et al. 2019

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“…When sintering pure WC powder, a small amount of tungsten hemicarbide W 2 C is unavoidably formed because the surface of the WC powder becomes oxidized when the fine powder is handled in the air. It should be expected that the presence of W 2 C in the bulk sintered WC material might reduce its mechanical properties [ 22 ].…”

Section: Resultsmentioning

confidence: 99%

Feasibility of Cobalt-Free Nanostructured WC Cutting Inserts for Machining of a TiC/Fe Composite

et al. 2021

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The paper presents results of investigations on the binderless nanostructured tungsten carbide (WC) cutting tools fabrication and performance. The scientific novelty includes the description of some regularities of the powder consolidation under electric current and the subsequent possibility to utilize them for practical use in the fabrication of cutting tools. The sintering process of WC nanopowder was performed with the electroconsolidation method, which is a modification of spark plasma sintering (SPS). Its advantages include low temperatures and short sintering time which allows retaining nanosize grains of ca. 70 nm, close to the original particle size of the starting powder. In respect to the application of the cutting tools, pure WC nanostructure resulted in a smaller cutting edge radius providing a higher quality of TiC/Fe machined surface. In the range of cutting speeds, vc = 15–40 m/min the durability of the inserts was 75% of that achieved by cubic boron nitride ones, and more than two times better than that of WC-Co cutting tools. In additional tests of machining 13CrMo4 material at an elevated cutting speed of vc = 100 m/min, binderless nWC inserts worked almost three times longer than WC-Co composites.

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“…Many reports suggest that it is a common phenomenon in WC cement carbide systems for W 2 C and C to appear as a result of WC decomposition during thermal interaction [41]. As some reports have suggested [42], the presence of W 2 C might reduce the mechanical properties of the composite, even though its microstructure looks very advantageous in term of the dimensions and distribution of the grains. In Figure 3b, WC in the form of numerous sub-micron grains, as well as some larger agglomerates can be seen scattered in the alumina matrix.…”

Section: Resultsmentioning

confidence: 99%

Analysis of the Electroconsolidation Process of Fine-Dispersed Structures Out of Hot Pressed Al2O3–WC Nanopowders

et al. 2021

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Fabrication of alumina–tungsten carbide nanocomposite was investigated. Characteristics of the densification and sintering were analyzed considering both the nano-size particle starting powders and the processing stages. Different heating rates were generated during densification and consolidation with a maximal load was applied only after a temperature of 1000 °C was reached. Due to the varying dominance of different physical processes affecting the grains, appropriate heating rates and pressure at different stages ensured that a structure with submicron grains was obtained. With directly applied alternating current, it was found that the proportion Al2O3 (50 wt.%)–WC provided the highest fracture toughness, and a sintering temperature above 1600 °C was found to be disadvantageous. High heating rates and a short sintering time enabled the process to be completed in 12 min, saving energy and time.

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Effects of Carbon Addition on Microstructures and Mechanical Properties of Binderless Tungsten Carbide

Cited by 45 publications

References 23 publications

A Review on Binderless Tungsten Carbide: Development and Application

A Review on Binderless Tungsten Carbide: Development and Application

Feasibility of Cobalt-Free Nanostructured WC Cutting Inserts for Machining of a TiC/Fe Composite

Analysis of the Electroconsolidation Process of Fine-Dispersed Structures Out of Hot Pressed Al2O3–WC Nanopowders

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