Effect of Fe/Ni ratio on the microstructure and properties of WC-Fe-Ni-Co cemented carbides
Introduction
Conventional cemented carbide processed using powder metallurgy technology is matrixed using refractory carbides (e.g., WC, TiC, Mo2C and TaC) with a soft and ductile metal Co as the binder phase [1], [2], [3], [4]. Due to its excellent wettability, good yield and work hardening behaviour, Co has been the most widely used element for producing the cemented carbide [5], [6], [7]. Co plays an important role in the bonding of WC grains. Since its first use, the WC-Co cemented carbide has been gaining importance for applications in cutting, mining, and drilling tools as well as in machining and wear resistant parts [4], [8], [9].
Currently, because cemented carbides are frequently exposed to severe service environments, alloys with a combination of a high hardness, wear resistance, toughness and corrosion resistance are required. However, the applications of WC-Co cemented carbides under severe conditions are restricted due to the disadvantages of using Co as the binder, namely, the resulting corrosion and oxidation resistance of the alloys. Furthermore, as a crucial yet scarce strategic metal, Co has exhibited increasing and unstable prices, and its adverse effect in terms of pollution should also be taken into consideration [8], [10], [11], [12]. Clearly, it is difficult for such a WC-Co system to meet the requirements for industrial applications due to the disadvantages mentioned above. It is, therefore, of common interest to find more cost-effective and environmentally benign metals to partially or completely replace Co without compromising the properties of cemented carbides [13]. A few studies have found that the corrosion and oxidation resistance of those of Co are inferior to that of Ni, and the hardness and wear resistance of Fe are relatively greater than that of Co [14]. Accordingly, the combination of Fe and Ni is considered to be an ideal alternative for replacing of Co because of its low toxicity, low pollution, good wettability with WC and excellent properties [13], [14].
Environmentally friendly cemented carbide that exhibits good performance has become a popular worldwide research topic. Fe-Ni-Co alloy is a promising binder for WC-based cemented carbides, since it has better ductility, greater strength, better wear resistance, greater corrosion resistance and better sinterability at relatively lower temperatures compared with metallic Co as a binder [8], [15]. Moreover, the properties of Fe-based cemented carbides can be further improved with heat treatment or deep cryogenic treatment [16], [17]. Recently, WC-Fe-Ni-Co cemented carbides have been widely studied due to their promising properties. Polini and co-workers [12] developed good quality and dense cemented carbides using a new binder phase prepared by sinter-hot isotactic pressing (HIP) with medium-grained WC and pre-alloyed Fe/Ni/Co powders. Chang et al. [15] investigated the sintering behaviour and properties of nanostructured WC-Co-Ni-Fe hard metal alloys and found that the sintered alloys possessed much better corrosion resistance and mechanical properties compared with WC-Co alloys. Zhou et al. [18] proposed a thermodynamic model for the C-Co-Fe-Ni-W system, and the calculated results are in good agreement with the experimental results. Gille et al. [19] reported that cemented carbides using the newly developed Fe/Ni/Co binder alloys could provide an alternative for some industrial applications where improved toughness and fatigue strength are required.
In these studies, it is noted that the changes of the binder composition are shown to have a significant effect on the properties of the cemented carbides [12], [19], [20], [21], [22]. Therefore, it is worthwhile to research the effects of different binder compositions. Su [20] and Zhang [21] et al. studied the changes in the properties of WC-Co-Ni cemented carbides with different Co/Ni ratios and found that when Co/Ni was 4:1, better mechanical properties and corrosion resistance were achieved than with the WC-Co alloys. Additionally, WC-Fe-Ni cemented carbides with different Fe/Ni (9:1, 8.5:1.5, 8:2, 7:3 and 5:5) ratios were also investigated by Schubert and his co-workers [22]. However, until now, only a few systematic studies have been conducted regarding the effects of the binder composition (different Fe/Ni ratios) on the microstructure, magnetic properties, mechanical properties, wear resistance and corrosion behaviour of WC-Fe-Ni-Co cemented carbides. Therefore, it is worthwhile to research the binder composition effects to achieve a better understanding of WC-Fe-Ni-Co cemented carbides with different Fe/Ni ratios towards applying them in industrial applications. In this study, WC-20(Fe-Ni-Co) cemented carbides were prepared with different Fe/Ni ratios and a constant Co content via low pressure sintering using a powder metallurgy technique, and the effects of different Fe/Ni ratios on the microstructure, magnetic properties, mechanical properties, wear behaviour and corrosion behaviour of WC-Fe-Ni-Co cemented carbides were investigated.
Section snippets
Preparation of cemented carbides
The characteristics of the raw powders used in this work are listed in Table 1. To investigate the effects of varying Fe/Ni ratios on the properties of WC-Fe-Ni-Co cemented carbides, the content of the binder phase was maintained at 20 wt%, and the ratio of Fe/Ni was altered while maintaining the Co content in the binder. The nominal compositions of these alloys are given in Table 2. The amount of gross carbon was adjusted to obtain the desired alloys with a two-phase region. The mixed powders
Phase constitution and microstructure analysis
Fig. 2 shows the XRD patterns of the WC-Fe-Ni-Co cemented carbides with different Fe/Ni ratios. As shown in Fig. 2, when the Fe/Ni ratio was between 1 and 1.67, the structure of the Fe-Ni-Co binder phase was mainly a face-centred cubic (fcc) γ-(Fe,Ni) solid solution. When the Fe/Ni ratio was approximately 2.2, a heterophase blend consisting of fcc γ-(Fe,Ni) and body-centred cubic (bcc) α-(Fe,Ni) was observed in Alloy 3. When the ratio was equal to or greater than 3, only bcc α-(Fe,Ni) was
Conclusions
In this work, the effects of different Fe/Ni ratios on the microstructure, magnetic properties, mechanical properties and corrosion behaviour of WC-20(Fe-Ni-Co) cemented carbide with a constant amount of Co were investigated, and the following conclusions can be drawn from the experimental results and discussion:
- 1)
With the increase in the Fe/Ni ratio, the crystal structure gradually changed from fcc γ-(Fe,Ni) to bcc α-(Fe,Ni) and more rounded WC grains were obtained, while the WC grain size
Acknowledgements
The authors gratefully acknowledge the financial support provided by Nonferrous Research Foundation of Hunan Province (Grant no. 20120619).
References (43)
- et al.
High-energy ball-milling combined with annealing of TiC powders and its influence on the microstructure and mechanical properties of the TiC-based cermets
Mater. Sci. Eng. A
(2017) - et al.
Strengthening zones in the Co matrix of WC–Co cemented carbides
Scr. Mater.
(2014) - et al.
Effect of C content on the microstructure evolution during early solid state sintering of WC-Co alloys
Int. J. Refract. Met. Hard Mater.
(2014) - et al.
WC-TiC-Ni cemented carbide with enhanced properties
J. Alloy. Compd.
(2008) - et al.
Parameters investigation during simultaneous synthesis and densification WC-Ni composites by field-activated combustion
Mater. Sci. Eng. A
(2003) - et al.
Study on the sintered characteristics and properties of nanostructured WC-15 wt% (Fe-Ni-Co) and WC-15 wt% Co hard metal alloys
J. Alloy. Compd.
(2015) - et al.
Y2O3- and NbC-doped ultrafine WC-10Co alloys by low pressure sintering
Int. J. Refract. Met. Hard Mater.
(2010) - et al.
Characterization and properties of MTCVD Ti(C,N) coated cemented carbide substrates with Fe/Ni binder
Int. J. Refract. Met. Hard Mater.
(2010) - et al.
Mechanical characterization of WC-10 wt% AISI304 cemented carbides
Mater. Sci. Eng. A
(2014) - et al.
Adherent diamond coatings on cemented tungsten carbide substrates with new Fe/Ni/Co binder phase
Thin Solid Films
(2006)
Effects of deep cryogenic treatment on the microstructure and properties of WC-Fe-Ni cemented carbides
Int. J. Refract. Met. Hard Mater.
Sintering behavior and mechanical properties of WC-10Co, WC-10Ni and WC-10Fe hard materials produced by high-frequency induction heated sintering
Ceram. Int.
Investigation into the sintered behavior and properties of nanostructured WC-Co-Ni-Fe hard metal alloys
Mater. Sci. Eng. A
Martensitic transformations in cermets with a metastable austenitic binder I: WC-(Fe-Ni-C)
Mater. Sci. Eng. A
Experimental investigation and thermodynamic assessment of the C-Co-Fe-Ni-W system
Int. J. Refract. Met. Hard Mater.
Advanced and new grades of WC and binder powder - their properties and application
Int. J. Refract. Met. Hard Mater.
Effects of Ni addition and cyclic sintering on microstructure and mechanical properties of coarse grained WC-10Co cemented carbides
Int. J. Refract. Met. Hard Mater.
Aspects of sintering of cemented carbides with Fe-based binders
Int. J. Refract. Met. Hard Mater.
Tribological behavior of WC-Ni cemented carbide irradiated by high-intensity pulsed ion beam
Surf. Coat. Technol.
Hardmetals with ‘‘rounded’’ WC grains
Int. J. Refract. Met. Hard Mater.
Variation of WC grain shape with carbon content in the WC–Co alloys during liquid-phase sintering
Scr. Mater.
Cited by (48)
Analysis of interface microstructure and element diffusion of WC-Co-Ni-Fe powder and M2 high-speed steel composite
2024, Materials Chemistry and PhysicsEffect of rare-earth elements on the interface of WC/α-Fe cemented carbide: A first-principles calculation
2023, Computational Materials ScienceInterface microstructure and abrasive wear properties of WC-iron matrix composites with Ni, Mo, Fe added to the preforms
2023, Journal of Materials Research and TechnologyHV-K<inf>IC</inf> property charts of cemented carbides: A comprehensive data collection
2022, International Journal of Refractory Metals and Hard Materials