Ceramic Griffith crack size

Strength test results on ceramic specimens show, in general, a large scatter. This follows from the fact, that in each individual specimen, the size of the critical crack is a little different. Rearranging Eq. (8) provides a relationship for the critical crack size (Griffith crack size) in a specimen ... 

For many ceramic materials, the ratio JQ/oy is of the order 1/100 /Tn. If a fracture starts in the interior of the component, the geometric correction factor for a pennyshaped crack (7 = 2/jt) can be used to calculate the corresponding Griffith crack size, giving a typical 80 pm. The size of critical flaws reflects the state of the art in... 

When an ordered array of monosized particles is sintered, the vacancies and grain boundaries create pores, cracks, and other flaws which are difficult to remove dming sintering. Pores are flaws about the size of the original ceramic particles in the final sintered ceramic. Grain boundaries are flaws that lead to cracks of a size equivalent to the size of the ordered domain. Both these flaws lead to the failure of the final ceramic piece according to Griffiths s analysis ... 

Static fatigue of ceramics occurs by the growth of subcritical surface cracks until they satisfy the Griffith criterion for fracture, i.e. the cracks reach a critical size [7]. This process can be strongly influenced by the... 

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