1 Scope
This Technical Report describes methods for evaluating tensile properties of metallic
materials (true stress-strain curve and derived parameters) using an instrumented indentation test.
The ranges of application of instrumented indentation tests are in line with the classification of ISO 14577‑1, but the range of force recommended is from 2 N to 3 kN.
This Technical Report includes the following three methods, all of which are sound
in principle, are capable of practical use and are appropriate for the specified materials.
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— Method 1: representative stress and strain;
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— Method 2: inverse analysis by FEA;
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— Method 3: neural networks.
In every method, tensile curves are derived from the experimentally measured indentation
force-depth curve, from which indentation tensile properties are evaluated. The three methods described all need different user strategies and
abilities to obtain the indentation tensile properties. The information required differs for each method and is described in detail in Clause 5.
The main assumption in the three methods is the absence of residual stress within
the test piece. Existing residual stress can affect the estimation of indentation tensile properties. A procedure for evaluating residual stress using an instrumented indentation test is given for reference in Annex A.