The Palmqvist method, or the Palmqvist toughness test, (after Sven Robert Palmqvist) is a common method to determine the fracture toughness for cemented carbides. In this case, the material's fracture toughness is given by the critical stress intensity factor KIc. It was developed c. 1962.
Approach The Palmqvist-method uses the lengths of the cracks from a number of Vickers indentions to determine the fracture toughness. The Palmqvist fracture toughness is given by
K Ic = 0.0028 HV P T {\displaystyle K_{\text{Ic}}=0.0028{\sqrt {\text{HV}}}{\sqrt {\frac {P}{T}}}} in units of MPa m {\displaystyle {\sqrt {\text{m}}}} , where HV is the Vickers hardness in N/mm2 (or MPa) (i.e., 9.81 x numerical HV), P is the indentation load in N (typically 30 kgf is used) and T is the total crack length (mm) after application of the indenter.
Notes
External links ISO 28079:2009, Palmqvist toughness test


