Acta Metallurgica Sinica (English Letters) ›› 2021, Vol. 34 ›› Issue (12): 1669-1678.DOI: 10.1007/s40195-021-01267-5

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Indentation Size Effect in β CuAlBe and Cu-2Be Alloys

Susana Montecinos1,2,3(), Sebastián Tognana1,3,4, Walter Salgueiro1,3,4   

  1. 1IFIMAT, Facultad de Ciencias Exactas, Universidad Nacional del Centro de La Provincia de Buenos Aires, Pinto 399, 7000 Tandil, Argentina
    2Consejo Nacional de Investigaciones Científicas y Técnicas CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires, Argentina
    3CIFICEN (UNCPBA-CICPBA-CONICET), Pinto 399, 7000 Tandil, Argentina
    4Comisión de Investigaciones Científicas de la Provincia de Bs. As, Calle 526 entre 10 y 11, 1900 La Plata, Argentina
  • Received:2020-12-29 Revised:2021-04-22 Accepted:2021-05-07 Online:2021-12-10 Published:2021-12-10
  • Contact: Susana Montecinos
  • About author:Susana Montecinos dmonteci@exa.unicen.edu.ar

Abstract:

The indentation size effect (ISE) was studied by instrumented nanoindentation and Vickers hardness measurements on polycrystalline copper, β CuAlBe pseudoelastic and age-hardenable CuBe alloys. Variations in the load-depth curves at different loads would suggest a change in the behavior of the materials as the load increases. Nanohardness was estimated at different loads taking into account the pile-up in each case, which was estimated from the images of the topography obtained by atomic force microscopy (AFM). The effect of the microstructure of Cu-2Be (wt%) samples on the ISE was also studied. For each copper alloy, the Nix and Gao model was applied to the hardness-depth curves, and significant differences were found for the parameters obtained. Cu is in the constant nanohardness regime for depths below 500 nm, while microhardness exhibits the ISE effect. The behavior of the nanohardness and the plastic strain with the depth is almost inverse. CuAlBe presents the lowest values of plastic strains due to the pseudoelastic effect, while Cu presents an almost constant value around 8%, which corresponds to the highest plastic strain obtained.

Key words: Hardness, Pseudoelasticity, Copper alloys, Plasticity, Indentation size effect