Toughness Measurement of Cemented Carbides with Chevron‐Notched Three‐Point Bend Test

Abstract

Plane‐strain fracture toughness is a critical property of metal matrix composites, especially for cemented carbides, ceramics, and tool materials. In this study, we have investigated, numerically and experimentally, the method involving three‐point bend test of a chevron‐notched specimen to evaluate fracture toughness of cemented carbides. A comprehensive formula is presented for a wide range of test dimensions and chevron notch angles. Cemented carbides with different toughness levels were tested. The proposed formula provides a more accurate and valid expression compared with existing methods. It offers an accurate, convenient, and practical method for toughness testing of cemented carbide, ceramics, tool materials, and other metal matrix composites.

Fracture toughness of cemented carbides: Testing method and microstructural effects

“…To be able to measure deflection of the testing sample, a linear variable differential transformer (LVDT) displacement gauge was used during the test. The stress intensity factor for a Chevron notched specimen loaded in flexure under three-point bending can be expressed as [18][19][20]:…”

Micropillar compression deformation of single crystals of α-Nb5Si3 with the tetragonal D8l structure

“…For the calculation of Y C (α 0 , α 1 ), the method proposed by Deng et al [20] was applied. Please refer to [20] for the details. [17].…”

“…at room temperature and at a constant displacement rate of 5 nm s -1 , as in our previous paper [17]. The fracture toughness value, K IC was evaluated from the maximum load (P max ) with numerical analysis using the equations proposed by Deng et al [17,20,21] (see Appendix for the details).…”

“…Fracture toughness was evaluated by micro-cantilever bend testing on a chevron-notched micro-beam specimen ( l : 12 μm, W : 4.5 μm, B : 3 μm, see Appendix) at room temperature and at a constant displacement rate of 5 nm s −1 , as in our previous paper [ 17 ]. The fracture toughness value, K IC was evaluated from the maximum load ( P max ) with numerical analysis using the equations proposed by Deng et al [ 17 , 20 , 21 ] (see Appendix for the details).…”

“…The fracture toughness, K IC was evaluated from the result of a single cantilever bend test for a chevron-notched micro-beam specimen with dimensions of l = 12 μm, W = 4.5 μm and B = 3 μm, and notch lengths a 0 and a 1 , and a crack length a ( Figure A1 ) using the following equation [ 20 , 21 ]). where P max is the maximum load reached during the bend test.…”