Modelling of the deformation and destruction of a TiNi-TiB2 metal-ceramic composite fabricated by direct laser deposition

Abstract

A pilot sample of a TiNi-TiB2 metal-ceramic composite has been developed. The sample implements a mechanism of multi-level strengthening using nanosize particles with sizes from tens of nm to 250 nm. The size of the strengthening particles in the micron range does not exceed 5 µm, which ensures their high tensile strength. The authors have developed a computer model of such a metal-ceramic composite that takes into account multi-level strengthening of the TiNi-TiB2 system: the TiNi matrix is indirectly reinforced by nano-sized particles and there is a direct reinforcement by micron-sized TiB2 particles. The authors have performed numerical studies of the mechanisms of deformation and destruction of the metal-ceramic composite with different percentages of content of reinforcing TiB2 particles. It has been demonstrated that a significant contrast between the mechanical properties of the intermetallide TiNi matrix and the reinforcing particles, regardless of the content of reinforcing particles, always leads to the formation of local areas of extension in the metal-ceramic composite. This leads to the destruction of reinforcing particles via the extension mechanism. In the case of high content (57–60%) of micron-sized reinforcing particles, this process of the destruction of strong particles via the mechanism of extension is taking place significantly later at a greater macroscopic deformation of the samples and at greater levels of stress.