Micro tensile testing and test volume
Micro tensile tests characterise materials at the microscale. They are indispensable whenever very small volumes (millimetres to micrometres) must be evaluated. This applies to electronics, medical parts, additively manufactured features and local weld regions where conventional tensile specimens are no longer realistic.
How does tensile testing work from macro to micro?
Conventional tensile tests with millimetre cross-sections provide stress-strain behaviour averaged over a large volume. However, microstructure governs strengthening, strength and ductility. Local properties can deviate significantly from macroscopic averages.
Example: welded joints. Filler addition and thermal input change the base material's microstructure. The heat-affected zone shows local variations in strength and ductility that must be quantified.
True flow curves on the microscale are highly relevant for FEM. They support the design of microsystems and the evaluation of heat-affected zones, coatings or additive structures.
Nanoindentation is a common complementary method when mechanical properties are needed on similar length scales, but micro tensile testing adds direct stress-strain information whenever a miniature specimen can still be extracted.
