Flakes

Randomly oriented internal thermal cracksRuptures in metal set up by stresses due to thermal differentials. (“shatter cracks”) in steels resulting from critical combinations of stress and hydrogen content. In a fracture surface, flakesRandomly oriented internal thermal cracks ("shatter cracks") in steels resulting from critical combinations of stress and hydrogen content. In a fracture surface, flakes appear as bright silvery areas; on an etched surface they appear as short discontinuous cracks.... More appear as bright silvery areas; on an etched surface they appear as short discontinuous cracks.