Microplasticity of biomorphic SiC/Al composite under uniaxial compression

Abstract

Inhomogeneity of the microplastic strain rate (deformation jumps) of a biomorphic SiC/Al composite under uniaxial compression has been studied by laser interferometry on the nanometer level. The value of strain rate jumps has been calculated from the deviation of the form of separate beats in the interferogram of a deformation from the standard form corresponding to a constant strain rate within one beat. In addition to strain rate oscillations extended by 100–180 nm along the displacement (the variation in the length of the specimen), peaks of small width and amplitude with a distance of 10–20 nm between them are observed, as well as peaks with a width of ∼ 50 nm. These peaks may be associated with the sizes of structural formations of an aluminum alloy (grains, subgrains, precipitates, etc.) or with the sizes of SiC nano- and microcrystals situated separately from large-grain crystals and surrounded by residual carbon. The results of this work offer hope to the possibility of enhancing plasticity and strength of biomorphic composites by increasing the fraction of fine-grain elements (< 1.5 µm) in their structure.