The First Exploration to Draw Stress-strain Curves and Calculate Tensile Test Results with Single Cycle Loading Data of Instrumented Indentation Test

The indentation depth is obtained by subtract the elastic deformation of the indentation instrument from the displacement data automatically collected by the indentation instrument, and then the indentation diameter is calculated. According to the series of formulas for testing the tensile properties by indentation method proposed by TABOR, the true stress, engineering stress and strain are calculated, the continuous stress-strain curve and lgW-lgd curve of indentation method are drawn, and the tensile strength, yield strength and tensile strain hardening exponent (n value) are calculated according to the two curves. The measured data show that there is a significant difference between the continuous stress-strain curve of indentation method and the stress-strain curve of tensile method. The measurement uncertainty of tensile strength, yield strength and n value measured by indentation method is analyzed in detail. The results show that the measurement uncertainty of tensile strength is less than 10% of the tensile strength value, while the relative measurement uncertainty of n value is significantly higher than that of tensile strength. At present, no reliable method for evaluating the uncertainty of yield strength measurement has been found.