Spark plasma sintering of pure TiCN: Densification mechanism, grain growth and mechanical properties

Fabrication and performances of WC‐Co cemented carbide with a low cobalt content

“…Figure 7B shows the mechanical performances of the sintered bulks. It is generally recognized that the hardness of WC‐Co composites is affected by degree of densification, WC content, and mean grain size of WC, on the basis of the following formula 43,44 : $$\begin{equation}H = K{d^{ - a}}\exp ( - b\rho )\end{equation}$$where H , $$\rho $$, and d are the Vickers hardness, the porosity, and the grain size of the alloy, respectively; K, a , and b are all constants. It can be found from Figure 7B that that hardness first raises and then drops, as the cobalt content increases.…”

“…The maximum Vickers hardness of cemented carbides without the addition of vanadium was 2234 HV30, which was obtained by vacuum sintering WC‐2 wt.%Co at 1450°C. When 0.5 wt.% VC is added, the WC grain size becomes finer, and therefore more grain boundaries are created, which will prevent dislocation migration between grains and plastic deformation according to the Hall–Petch equation 43,44 : $$\begin{equation}\sigma ={\sigma ^*} + k{d^{ - 1/2}}\end{equation}$$where $$\sigma $$ is the yield strength; d is the grain size, and $${\sigma ^*}$$ and k are constants. Owing to the finer grain sizes, the hardness of the alloy after adding VC is higher than WC‐3 wt.%Co.…”

“…Figure 7B shows the mechanical performances of the sintered bulks. It is generally recognized that the hardness of WC-Co composites is affected by degree of densification, WC content, and mean grain size of WC, on the basis of the following formula 43,44 :…”

Densification kinetics of boron carbide with medium entropy alloy as a sintering aid during spark plasma sintering

“…The steady‐state creep strain, ε , can be described as: where ε is the creep rate, t the time, A a constant, Φ the diffusion coefficient, μ the shear modulus, b the Burgers vector, k the Boltzmann's constant, T the thermodynamic temperature, G the grain size, σ the macroscopic applied pressure, p the grain size exponent and n the stress exponent. For a fixed soaking temperature and a low relative density, shear modulus, and grain size exponent can be thought as a constant.…”

“…The experiment height values subtracted the blank test height values corresponding to the real height of the samples. The instantaneous sample relative density D can be calculated from the instantaneous height of the sample L via the following equation: where D f and L f are the final relative density and final height of the samples, respectively.…”