Palmqvist method

Materials testing
Palmqvist method
Determined crack lengths from a Vickers indention.
Technical information
Searched property	Fracture toughness
Year developed	1962[1]
Practical use	Determination of the fracture toughness for cemented carbides.
Website ISO-standard	ISO 28079:2009, Palmqvist toughness test

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 materials fracture toughness is represented by the critical stress intensity factor K_IC.^[2]

Approach

The Palmqvist-method uses the lengths of the cracks from a number of Vickers indentions to determine the fracture toughness.^[2] The critical stress intensity factor is then given by:

${\displaystyle K_{Ic}=6.2*{\sqrt {\frac {HV50}{\sum _{Cracklengths}\,}}}}$ with the unit ${\displaystyle Pa{\sqrt {m}}}$.

Notes

1. S. Palmqvist, Occurrence of crack formation during Vickers indentation as a measure of the toughness of hard materials, Arch Eisenhuettenwes, 33 (1962) 629-333.
2. Detta är hårdmetall, Digital compendium - Sandvik, (in Swedish), Retrieved 22 January 2016