REVERSE SHEAR OF SHEAR BANDS AND ANNEALING EMBRITTLEMENT IN AMORPHOUS ALLOY

Shear bands produced by bending before annealing could be reversed if isothermally annealed or continuously heated before the onset of embrittlement. The activation energy for the onset of embrittlement is 69-72 kcal/mol similar to that of crystallization, 67-68 kcal/mol, if the latter is evaluated at the same X-ray first peak height. The activation energy of crystallization based on Kissinger plots of DSC data is erroneous, since samples at the onset or peak of crystallization in the thermogram do not have similar X-ray first peak heights. It seems that whatever structural modification is inside the shear bands is stable during annealing until embrittlement and that the embrittlement is related to the incipience of crystallization.