Nanomechanical characterization of Ti-base nanostructure-dendrite composite

The present work represents the first localized nanomechanical analysis of the single phases present in an alloy, providing a better understanding of the macroscopic behaviour of the material. The Ti60Cu14Ni12Sn4Nb10 and Ti60Cu14 Ni12Sn4Ta10 alloys under investigation show a very similar elastic response of the nanostructured matrix in spite of a slightly higher hardness in the latter. Nevertheless, the dendritic phase exhibits substantially higher values of hardness for both alloys, with an increase of about 32% in both cases. The elastic modulus increases by up to 36% in the Ta-containing alloy and by up to 23% in the Nb-containing alloy, compared to the matrix. The different nanomechanical response explains, together with the effect of the dendrites restricting crack propagation, the increased ductility of the Nb-containing alloy compared with the Ta-containing alloy.