In the YouTube video Ductility Test, I saw a black substance undergo a ductility test. It appeared to be as ductile as silly putty although silly putty is just a very viscous liquid. It seems that it can keep being pulled thinner and thinner. I couldn't find the name of the substance in the video. I just want to know the name of that substance. Once I learn the name of that substance, I can ask another question about the properties of that substance.
I'll ask whether it's a solid unlike silly putty. I know it started off as a liquid but I'll ask whether it got turned into a solid or just a very viscous liquid. I'll ask "If it's a solid, what is its yield strength?" If it has a higher yield strength than the typical chromium steel, it could be very revolutionary because it cannot sustain crack propagation and therefore cannot be weakened much by the presence of a crack.