Preparation and mechanisms of cemented carbides with ultrahigh fracture strength

Liu, Xianjing; Song, Xiaoyan; Wang, H.; Wang, X.; Guo, Guangsheng

doi:10.1107/s1600576715012832

Cited by 37 publications

(17 citation statements)

References 37 publications

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“…However, as the volume fraction of the metal binder in the cemented carbides is much smaller than that of WC, the plastic accommodation from the binder is strongly restricted by the contiguity of WC grains. Thus, improving the toughness of the hard carbide matrix may effectively enhance the resistance against the transgranular fracture of the cemented carbide (Liu et al, 2015). In this respect, experiments and molecular dynamics simulations based on nanoindentation and uniaxial compression have been performed to examine the deformation characteristics of WC (Fang et al, 2019;Bl'anda et al, 2014;Csaná di et al, 2015;Tarragó et al, 2016;Liu et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

How hard metal becomes soft: crystallographic analysis on the mechanical behavior of ultra-coarse cemented carbide

Hu¹,

Liu²,

Hou³

et al. 2019

Acta Crystallogr B Struct Sci Cryst Eng Mater

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Investigation into the temperature dependence of the mechanical behavior of ultra‐coarse grained cemented carbide materials is highly demanded due to its service conditions of concurrent applied stress and high temperature. In the present study, based on the designed experiments and microstructural characterization combined with crystallographic analysis, the evolution of slip systems, motion and interaction of dislocations with temperature are quantified for the WC hard phase. Mechanisms are proposed for the formation of the sessile dislocations in the main slip systems at the room temperature and the glissile dislocations in the new slip systems activated at high temperatures. Furthermore, the correlation of the plastic strain and fracture toughness with the temperature‐dependent slip activation, dislocation reaction and transformation is explained quantitatively. Enlightened by the present findings, potential approach to enhance the high‐temperature strength of ultra‐coarse cemented carbides based on WC strengthening was suggested.

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Section: Introductionmentioning

confidence: 99%

How hard metal becomes soft: crystallographic analysis on the mechanical behavior of ultra-coarse cemented carbide

Hu¹,

Liu²,

Hou³

et al. 2019

Acta Crystallogr B Struct Sci Cryst Eng Mater

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“…It is generally considered that the plasticity and toughness of the cermets are determined by the binder metal due to its intrinsic mechanical features (García et al, 2018). However, in our previous work, we found that the carbide matrix is also resistant to transgranular fracture through its deformation behavior (Liu et al, 2015). Therefore, to distinguish the contributions of carbide matrix and binder to the plasticity of cermets is of great importance (Fischmeister et al, 1988;.…”

Section: Introductionmentioning

confidence: 88%

Distinguishing contributions of ceramic matrix and binder metal to the plasticity of nanocrystalline cermets

Liu

Hou

et al. 2020

IUCrJ

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Using the typical WC–Co cemented carbide as an example, the interactions of dislocations within the ceramic matrix and the binder metal, as well as the possible cooperation and competition between the matrix and binder during deformation of the nanocrystalline cermets, were studied by molecular dynamics simulations. It was found that at the same level of strain, the dislocations in Co have more complex configurations in the cermet with higher Co content. With loading, the ratio between mobile and sessile dislocations in Co becomes stable earlier in the high-Co cermet. The strain threshold for the nucleation of dislocations in WC increases with Co content. At the later stage of deformation, the growth rate of WC dislocation density increases more rapidly in the cermet with lower Co content, which exhibits an opposite tendency compared with Co dislocation density. The relative contribution of Co and WC to the plasticity of the cermet varies in the deformation process. With a low Co content, the density of WC dislocations becomes higher than that of Co dislocations at larger strains, indicating that WC may contribute more than Co to the plasticity of the nanocrystalline cermet at the final deformation stage. The findings in the present work will be applicable to a large variety of ceramic–metal composite materials.

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“…As a class of intrinsically brittle materials, the fracture toughness of cemented carbides is generally considered as the bottleneck of its mechanical properties. Thus, the improvement of fracture toughness while controlling the decrease in hardness and hence the enhancement of the fracture strength of cemented carbides is very challenging, especially as grain size decreases to the nanoscale (Cha et al, 2001;Liu et al, 2012Liu et al, , 2015. For nanocrystalline cemented carbides, due to the decrease of WC grain size, an ultrahigh hardness can be obtained.…”

Section: Introductionmentioning

confidence: 99%

Crystal defects responsible for mechanical behaviors of a WC–Co composite at room and high temperatures – a simulation study

Fang

Liu

et al. 2019

Acta Crystallogr B Struct Sci Cryst Eng Mater

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The microstructure evolution and changes in the structures of crystal defects of the nanocrystalline WC-Co composite in the process of uniaxial compression were studied by simulations at both room and high temperatures. The deformation processes were demonstrated as a function of stress and temperature for the stages prior to and after yielding of the composite. The Peierls stresses were evaluated for Co and WC dislocations with increasing temperature. The deformation mechanisms for each stage of the stress-strain curve were disclosed, in which the effect of temperature was clarified. It was found that with the increase of stress, from elastic deformation to plastic deformation then to yielding of the composite, the dominant mechanisms are grain boundary migration, formation and motion of dislocations in Co, concurrent motion and reaction of dislocations in Co and WC, and then rotation of WC grains in combination with motion of Co and WC dislocations. At the yielding stage, sliding of WC grain boundaries plays an increasingly important role in the contribution to plastic deformation at high temperatures. With strain the proportion of mobile dislocations decreases, and dislocations pile up at triple junctions of WC grains, WC/WC grain boundaries and WC/Co phase boundaries in priority order, leading to the nucleation and propagation of microcracks in these regions.

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Preparation and mechanisms of cemented carbides with ultrahigh fracture strength

Cited by 37 publications

References 37 publications

How hard metal becomes soft: crystallographic analysis on the mechanical behavior of ultra-coarse cemented carbide

How hard metal becomes soft: crystallographic analysis on the mechanical behavior of ultra-coarse cemented carbide

Distinguishing contributions of ceramic matrix and binder metal to the plasticity of nanocrystalline cermets

Crystal defects responsible for mechanical behaviors of a WC–Co composite at room and high temperatures – a simulation study

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