Engineering:Palmqvist method
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| 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 material's fracture toughness is given by the critical stress intensity factor KIc.[2]
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[2]
- [math]\displaystyle{ K_{\text{Ic}} = 0.0028\sqrt{\text{HV}}\sqrt{\frac{P}{T}} }[/math] in units of MPa[math]\displaystyle{ \sqrt{\text{m}} }[/math],
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
- ↑ S. Palmqvist, Occurrence of crack formation during Vickers indentation as a measure of the toughness of hard materials, Arch Eisenhuettenwes, 33 (1962) 629-333.
- ↑ 2.0 2.1 Roebuck, Bryan; Bennett, Eric; Lay, Lewis; Morrell, Roger (2008). "Palmqvist Toughness for Hard and Brittle Materials". National Physical Laboratory. http://eprintspublications.npl.co.uk/1566/1/mgpg9.pdf.
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