Structure and phase composition of SHS composites based on Al–Ti–B system with different Al content

Abstract

The paper deals with the influence of the Al content in the initial Al–Ti–B system on self-propagating high-temperature synthesis (SHS) processes, structure, and phase composition of synthesized products. It is found that the higher Al content leads to a temperature decrease of exothermic reaction and changes its wavefront propagation from layerwise to spinwise multiple locations. SHS products obtained from the Al–Ti–B system contain titanium diboride (TiB2) and aluminum (Al) phases. The weight content of phases in SHS products depends on the Al content in the initial powder mix and approximately matches the weight content of its components. The higher Al content provides a decrease in the size of the coherent scattering region for detected phases. SHS products obtained from the Al–Ti–B system with 10 wt% Al, consist of separate TiB2 particles coated with aluminum film. The Al content increased up to 30 and 60 wt%, provides the formation of the metal matrix structure. In this case, synthesis products consist of the aluminum matrix with TiB2 particles distributed inside. It is found that the growth in the Al content from 10 to 60 wt% in the initial Al–Ti–B system, results in the size reduction of TiB2 particles in SHS products from 3.37 to 0.41 μm, respectively.