I have done destructive strength testing on carbon fiber. It would not shatter like porcelain. Carbon fiber is made of thin, very strong but very flexible stands of carbon embedded in more brittle resin (plastic). The resin by itself probably would shatter. Carbon fiber will snap suddenly as the resin fails, but the fibers keep it from flying apart.
With steel, it would depend very much on the alloy. Some are very ductile (will bend very far without breaking) whereas some are more brittle and actually will shatter with enough force.
This video gives a good idea of how steel would compare to carbon fiber. Carbon fiber starts at 3:57 and high speed steel (a very brittle steel) at 6:19. There is no ductile steel, but 6061aluminum at 2:48 fails pretty much the same way just with a lower force.
I have done destructive strength testing on carbon fiber. It would not shatter like porcelain. Carbon fiber is made of thin, very strong but very flexible stands of carbon embedded in more brittle resin (plastic). The resin by itself probably would shatter. Carbon fiber will snap suddenly as the resin fails, but the fibers keep it from flying apart.
With steel, it would depend very much on the alloy. Some are very ductile (will bend very far without breaking) whereas some are more brittle and actually will shatter with enough force.
This video gives a good idea of how steel would compare to carbon fiber. Carbon fiber starts at 3:57 and high speed steel (a very brittle steel) at 6:19. There is no ductile steel, but 6061aluminum at 2:48 fails pretty much the same way just with a lower force.
https://youtu.be/ifOzrOgpI4g