Grain size dependence of hardness and fracture toughness in pure near fully-dense boron carbide ceramics

Room temperature fracture toughness and hardness of spark plasma sintered pure B4C ceramics with grain sizes ranging from 120 nm to 17 μm have been studied. Vickers indentation and single edge V-notched beam (SEVNB) techniques have been used to measure hardness and fracture toughness, respectively. A critical analysis of the results derived from these two techniques has been carried out and the conditions for proper comparison of the derived results are discussed. The results have shown that hardness follows the Hall–Petch dependence with either grain size or twin spacing when the effect of porosity is corrected for. On the contrary, fracture toughness is found to be essentially grain size independent. The value of this quantity is ∼2 MPa m1/2

Abrasive wear rate of boron carbide ceramics: Influence of microstructural and mechanical aspects on their tribological response

Boron carbide ceramics are amongst the most exciting materials in the family of ultra-high hardness ceramics and they are used extensively in tribological applications. This research work is a pioneering contribution on the analysis of the abrasive wear resistance of boron carbide as a function of grain size and porosity. In contrast to most ceramics, it is concluded that grain size is not directly relevant to the wear resistance, whereas porosity and hardness play the main role. The absence of surface pullout by brittle fracture is a relevant experimental feature in this material which results in mild wear. Our results are rationalized in terms of the classical Rabinowicz model, which gives a reasonable description of the wear response

Abrasive wear rate of boron carbide ceramics: Influence of microstructural and mechanical aspects on their tribological response

Boron carbide ceramics are amongst the most exciting materials in the family of ultra-high hardness ceramics and they are used extensively in tribological applications. This research work is a pioneering contribution on the analysis of the abrasive wear resistance of boron carbide as a function of grain size and porosity. In contrast to most ceramics, it is concluded that grain size is not directly relevant to the wear resistance, whereas porosity and hardness play the main role. The absence of surface pullout by brittle fracture is a relevant experimental feature in this material which results in mild wear. Our results are rationalized in terms of the classical Rabinowicz model, which gives a reasonable description of the wear response