Precrack preparation problem on WC/Co CT sample

Hi All
Can someone help mi find any method to prepare SHARP precrack on CT sample of Wc/Co ?
I need to gain R-curve but I have no idea how to make proper
preparation of ma samples. What I did already 1. Made a incline notch 2. Vickers Indent (no indents crack) Samples were polished by 9mikron and marked by 1mm step After that stress concetration is too big - I broke sample
Fracture toughness is about 13-15
Fatiging it does not make sense because of fine grain size and I think there is no fatigue effect in ceramics
Has anyone experience of that kind of tests or an idea how to test this really brittle material?
Marcin Knec
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
WC - Co is ceramic particles in a metal matrix. It does fatigue but you are correct about the fine grain properties.
What the hey, give the fatiguing a shot.
good luck, Tom
P.S. You might try the ASM web site. They have a society of carbide tool engineers.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ok thank You. I'll try to find a little deeper :) because society of carbide tool eng is providing tool for cuting only.
Marcin Knec.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.