SEDL / STP / STP947-EB / STP20027S

Significance of Ductility and New Methods of Measuring the Same

Rolff, R
Metrologist, Schering, A. G., Plating Division,

Pages: 13    Published: Jan 1987

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Abstract

Cracks in plated metal layers will develop if the sum of the tensile stresses exceeds the tensile strength of the plating. Stress will concentrate on irregularities in the plated surface, such as pores and inclusions. The ductility of the plating is the most important influence on the stress concentration factor. Therefore, its measurement is essential for the evaluation of a plated surface. Two methods of measuring ductility are described, both using the effect of bulging the plating, thereby exceeding the tensile strength of the plated surface layer. As the deformation can be described mathematically, it is possible to convert the results into linear extensibility, that is, the physical value of the ductility.