Mechanical assessment of ultrafine-grained nickel by microcompression experiment and finite element simulation

Over the past two decades, nanoindentation has been the most versatile method for mechanical testing at small length scales. Because of large strain gradients, it does not allow for a straightforward identification of material parameters such as yield and tensile strength, though. This represents a major drawback and has led to the development of alternative microscale testing techniques with microcompression as one of the most popular ones today. In this research, the influence of the realistic sample configuration and unavoidable variations in the experimental conditions is studied systematically by combing in-situ microcompression experiments on ultrafine-grained nickel and finite element simulations. It will be demonstrated that neither qualitative let alone quantitative analyses are as straightforward as they may appear, which diminishes the apparent advantages of microcompression testing.