Elastic-plastic properties of mesoscale electrodeposited LIGA nickel alloy films: microscopy and mechanics

The elastic-plastic properties of mesoscale electrodeposited LIGA Ni alloy specimens are investigated as a function of specimen size, strain rate, and material composition. Two material compositions are studied: a high-strength fine-grained Ni-Fe alloy and a high-ductility coarse-grained Ni-Co alloy. The specimens have thicknesses of approximately 200 mu m and gauge widths ranging from 75 mu m to 700 mu m. Tensile tests are conducted at strain rates of 0.001/s and 1/s using tabletop loading apparatuses and digital image correlation (DIC) for strain measurement. For each test condition, the apparent Young's modulus, yield strength, ultimate tensile strength, and strain hardening exponent and strength coefficient are extracted from the tensile tests. The true strains to failure are also assessed from fractography. Size, rate, and composition effects are discussed. For most properties, the statistical scatter represented by the standard deviation exceeds the measurement uncertainty; the notable exceptions to these observations are the apparent Young's modulus and yield strength, where large measurement uncertainties are ascribed to common experimental factors and material microplasticity.

Automated summary

The study investigates the elastic-plastic properties of mesoscale electrodeposited LIGA Ni alloy specimens as influenced by specimen size, strain rate, and material composition. The results show that size, rate, and composition have significant effects on the material properties, particularly on the apparent Young's modulus and yield strength.