Cracking and the Indentation Size Effect for Knoop Hardness of Glasses
George D. Quinn, P Green, K Xu
The Knoop Hardness of five glasses as measured over a wide range of indentation loads. Hardness decreased with increasing load in accordance with the classic indentation size effect (ISE). At moderate loads, cracking dramatically altered the indentation sizes and the ISE in three of the five glasses. Cracked indentations were as much as 10 m longer than uncracked indentations made under identical conditions.