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Fracture Toughness Testing of Polycrystalline Diamond

IP.com Disclosure Number: IPCOM000234778D
Publication Date: 2014-Feb-04
Document File: 2 page(s) / 66K

Publishing Venue

The IP.com Prior Art Database

Abstract

A diametral compression technique was used to evaluate the fracture toughness of a polycrystalline diamond (PCD) material. The technique showed good results and is suitable for use at higher temperatures.

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Fracture Toughness Testing of Polycrystalline Diamond

Summary

A diametral compression technique was used to evaluate the fracture toughness of a polycrystalline diamond (PCD) material.  The technique showed good results and is suitable for use at higher temperatures.

Experimental Procedures

A Nd-YAG laser was used to cut PCD samples of nominal grain size 12 micron to an outer diameter of 12.27 mm with a through notch of dimensions 6.13 mm length and a width of 0.2 mm.  The fracture toughness samples were loaded to failure using the configuration shown in figure 1.  A combination of copper and adhesive carbon tape was used to keep samples aligned and to provide sufficient compliance to avoid damage to the edges of the PCD disks during compressive loading.  A displacement rate of 0.5 mm/min was employed during the tests.  No precracking was performed on the specimens.  Chevron notching is helpful to ensure that the crack propagates in the expected direction.  

Figure 1.  Specimen dimensions and loading configuration used in fracture toughness testing.

Results

The fracture toughness was determined according to the relations (Atkinson, et al, 1982), (Singh and Shetty, 1988)

                                                                                           (Equation 1)

where Pc is the fracture load, a is the half length of the through slot, R is the radius of the disk specim...