Fracture Toughness of TiB2

A clearer indication of the role of grain size in the optimization of the mechanical properties of TiB2 is provided by the fracture toughness as measured by the mode I critical stress intensity factor KIc. For fully dense specimens at room temperature, having a mass fraction of TiB2 ⩾ 98 %, KIc appears to have a maximum value for a mean grain size of 5 μm ⩽ g ⩽ 12 μm. The values may be influenced by three potentially significant factors: grain size, measurement method, and chemical impurity content. A statistical factor analysis of these data indicates that 75 % of the variability from the mean may be attributed to the variation of the mean grain size. The role of residual Ni impurities was considered explicitly in Ref. and Ref. where, neglecting the influence of grain size, it appeared that toughness increased with Ni content. However, taking into account the effect of grain size, the principal influence is seen to be microstructural rather than chemical. Combining this result that g < 10 μm is needed to optimize σf, the optimum grain size for TiB2 should be in the range of 5 μm ⩽ g ⩽ 10 μm. At the optimum, KIc = (6.2±0.5)MPa·m1/2. If you are looking for high quality, high purity, and cost-effective Titanium diboride, or if you require the latest price of Titanium diboride, please feel free to email contact mis-asia.

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