Alumina grain-size hardness effect

Tabk 2. Parameters of a least squares fit (Eqs (3) and (3a)) for the load effect in the hardness of alumina ceramics with different grain sizes (Fig. 4). 

Figure 8. Grain size effects in the hardness of alumina ceramics (HV-10, triangies), and indentation size effect (load influence) in the hardness of sapphire (squares). For HVIO vaiues, the lower x-axis gives the average grain size (data for sapphire indicated at 1000 pm). For the curves describing the size effect in sapphire, the upper x-axis represents the length of the Vickers diagonal (n = 1) or the plastic zone size ( = 4) [6,16]. See Fig. 2 (p. 166) for theoretical background.

A. Krell, Effects of load, grain size, and grain boundaries on the hardness of alumina, Proc. 22nd Cocoa Beach Conference (20-24 January 1998), American Ceramic Society, Westerville,... 

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