Study of the indentation size effect in beta CuAlBe and Cu-2Be alloys

S. MONTECINOS; S. TOGNANA; W. SALGUEIRO

Acta Metallurgica Sinica (English Letters)

Springer

Año: 2021

1006-7191

The indentationsize effect ISE was studied by instrumented nanoindentation and Vickers hardnessmeasurements on polycrystalline copper, β CuAlBe pseudoelastic and age-hardenableCuBe alloys. Variations in the load-depth curves at different loads wouldsuggest a change in the behavior of the materials as the load increases. Nanohardness wasestimated at different loads taking into account the pile-up in each case,which was estimated from the images of the topography obtained by AFM. Theeffect of the microstructure of Cu-2Be (wt.%) samples on the ISE was alsostudied. For each copper alloy, the Nix and Gao model was applied to thehardness-depth curves, and significant differences were found for the parametersobtained. Cu is in the constant nanohardness regime for depths below 500 nm,while microhardness exhibits the ISE effect. The behavior of the nanohardnessand the plastic strain with the depth is almost inverse. CuAlBe presents thelowest values of plastic strains due to the pseudoelastic effect, while Cu presentsan almost constant value around 8 %, which corresponds to the highest plasticstrain obtained.