Why does quenching a metal result in brittleness?
Not a metallurgist, but … I suspect it’s to do with the rapid cooling not allowing large crystals to grow which would interlock and increase the solid’s strength. On the other hand, it may be a much more complicated effect and you would need to look at the phase diagram to see if some metastable mixture of ‘high temperature’ materials causes the problems. I’m sure a good ‘Google’ for “quenching of metals” would give you some good ideas.
