Die experimentelle Bestimmung von Stapelfehlerenergien kubisch-flächenzentrierter Metalle.

The present paper gives experimental and theoretical results which enabel us to determine the absolute values of stacking-fault energies of face-centred cubic metals from the stress-strain-curves of single crystals. The activation energy for the crossslip of screw-dislocations is calculated as a function of the stacking-fault energy γ, the applied shear stress τ, and the size of the piled-up dislocation groups. An experimental value for the activation energy for cross-slip in copper is deduced from the strain-rate dependence of the shear stress τ at the beginning of stage III of the stress-strain-curve. Comparison between experiment and theory gives γ=170 ergs/cm. The determination of the stacking-fault energy of other f.c.c. metals is possible by comparing the temperature dependence of τ. Experimental results are given for Au and Cu. Data from the literature are used for Ag, Ni, and Al. We find γ= 30 ergs/cm. The difference in stacking-fault energy of Cu and Au is much larger than was anticipated. It is substantiated, however, by a number of observations discussed in the paper. Constriction energies calculated on the basis of the newly determined stacking-fault energies are given. [ABSTRACT FROM AUTHOR]