SHS processes, structure and phase composition of hybrid compositional materials produced from (Al-Tiad)–(Ti-2B) system powder at different Tiad content

Abstract

The paper studies processes of self-propagating high-temperature synthesis (SHS) in the (Al-Ti_ad)–(Ti-2B) system powder and the structure and phase composition of the obtained hybrid compositional materials, depending on the content of additional titanium (Ti_ad) introduced in the initial powder mix. It is shown that the higher Ti_ad content leads to the temperature rise and more intensive SHS processes. The Ti_ad content of 5, 10 and 30 wt% provides the formation of hybrid metal matrix composite Al–Al₃Ti–TiB₂. The content of Al₃Ti phase in the SHS products increases with increasing Ti_ad concentration in the initial powder mix, while the content of the aluminum matrix reduces. Further growth in the Ti_ad content up to 50 wt% significantly modifies the phase composition of SHS products. The latter have no aluminum phase, but have new AlTi, cubic Al₃Ti, and orthorhombic and cubic TiB phases. The paper proposes formation mechanisms of the structure and phase composition of synthesized hybrid metal matrix composites Al–Al₃Ti–TiB₂. It is supposed that these hybrid materials can be used as a hardening additive to the powder mix for the SHS products. Hardening additives can be utilized both in conventional powder metallurgy and selective laser sintering, selective laser melting. The best content of hybrid metal matrix composite Al–Al₃Ti–TiB₂ added to the primary material, varies between 5 and 10 wt%. It is supposed that at such a concentration, the material plasticity lies within the tolerable limits; its strength, hardness, wear resistance, and oxidation stability being grown.