Palmqvist method
# Palmqvist method

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 $K_{Ic}.$

## 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

    $K_{\text{Ic}}=0.0028{\sqrt {\text{HV}}}{\sqrt {\frac {P}{T}}}$ in units of MPaFailed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "http://localhost:6011/en.wikipedia.org/v1/":): {\displaystyle \sqrt{\text{m}}} ,

where HV is the Vickers hardness in $N/mm^2$ (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.

