Addressing the indentation size effect (ISE) in cono-spherical nanoindentation test using a nonlocal crystal plasticity model

Napat Vajragupta, Ruhr-Universit├Ąt Bochum, Bochum, Germany

The indentation size effect (ISE) is an important phenomenon observed in the nanoindentation test. ISE is defined as an increase in hardness with decreasing the indentation depth. Therefore, the objective of this work is to investigate ISE observed in the cono-spherical nanoindentation test using a micromechanical modeling approach. In the first step, series of nanoindentation test using cono-spherical indenter tip are performed on the selected grain with different maximum forces in order to investigate their influences on pile-up and sink-in behavior. Secondly, nanoindentation tests are simulated using a nonlocal crystal plasticity model which are derived based on the concept of the geometrically necessary dislocations (GND) density tensor. With an iterative procedure, model parameters are adapted to yield an optimal agreement between experiment and simulation. In the final step, parameterized nanoindentation simulations are in-depth studied and validated with TEM analysis.

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Session T2: Tuesday, 26 June 2018

Start: 03:15 p.m.
End: 03:30 p.m.