Variation of strain ratio in cube plane of copper

Abstract

Strain-ratio values have been calculatedfor the following orientations of the tensilespecimen axis: 〈100〉, 〈10 10〉, 〈810〉, 〈510〉, 〈310〉, 〈210〉, 〈320〉, and 〈110〉. The results obtained made possible the determination of the distribution of the strain ratio in the {001} plane of an fcc metal. Theoretical results were verified in experiments on copper single crystals with the folio wing orientations: 〈100〉, 〈10 10〉, 〈510〉, 〈310〉, 〈210〉, 〈320〉, and 〈110〉. In each case, the single crystal was stepwise tensile tested and the strain ratio-true elongation (R–€) relationship was established, the extrapolation back to €=0 enabling the determination of the R ₀ coefficient. Good agreement between the calculated strain-ratio values and the experimental R ₀ coefficients was demonstrated. It was shown that an earlier prediction that the strain-ratio value for 〈110〉 orientation should be equal to zero was caused by the confusion of the strain-ratio value calculated at the limit of uniform elongation with its value obtained by extrapolation.