Vickers micro-indentation for the elasto-plastic characterisation of thin layers

摘要

A method is proposed for characterising components whose geometry rules out traditional tensile testing as a means of determining their elasto-plastic properties, especially if the components' manufacturing process is expected to have a significant influence on these properties. Suitable sets of material parameters are identified that fully characterise both the elasto-plastic and indentation behaviour of tested aluminium alloys. Based on a series of finite element simulations of Vickers indentations, a surrogate model is built to map the elasto-plastic parameters to indentation parameters for a wide range of alloy behaviour. The genetic algorithm is then employed to solve the inverse problem, that is, to work backwards from indentation to elasto-plastic parameters, allowing predictions of stress-strain curves from experimental indentation data. The developed characterisation process is shown to be capable of predicting quite well the general trends in an alloy's elasto-plastic behaviour. Scope for further work, which could improve the results, is identified.