Simulating residual stresses in ribbons of amorphous metallic alloys

A new method of simulation of residual stresses in ribbons of amorphous metallic alloys is proposed. The model considers the total deformation remaining in an amorphous metallic alloy during the quenching from liquid state to be the sum of elastic (residual ductile-elastic) and thermal deformations. The latter is related to the temperature through the linear coefficient of thermal expansion of the material. It is assumed that incompatibility of the residual deformations is the cause of residual macro-stresses. The thickness of the ribbon is considered to be much less than the other dimensions. Residual stresses on the free surface (not in contact with the drum) are assumed to be equal to zero. The results are discussed for an amorphous alloy: Fe 50Ni30B20. Concerns related to the development of technology for amorphous metallic alloys production include: when curvature radius increases, the curvature accordingly decreases; the value of the stress relaxation factor decreases upon contact of the ribbon with the surface of the drum; increase of the drum temperature and length of the field of its contact with the solidified ribbon, leading to a decrease of ribbon curvature. Copyright © 2010 by ASTM International.