Duplex stainless steel centrifuge brittle failure

So some people say brittle is anything below 0.2 percent, which is the yield point of a metal. Some people, and this is in the pipeline business, will say the yield point is defined at 0.5 percent, which is two and a half times as great. Some people will say you need to have five percent ductility to be ductile. Let's just say anything above one percent is ductile and means the thing has stretched. I didn't bring the sample, but I passed a sample around last time, my brittle centrifuge, and if you look very carefully, just a little bit of stretch before the thing snapped. It's a continuous spectrum of materials. Something very brittle like glass, depending on the flaw size, could fracture anywhere along that elastic limit. Things that fail out here above five percent strain are clearly ductile. They stretch like this, the Silly Putty. Things that are in between are sort of beauty in the eye of the beholder.