Effects of magnesium on initial temperature and mechanical activation on combustion synthesis in Ti–Al–Mg system

Abstract

Nowadays the investigation of new lightweight alloys based on titanium aluminides is of great interest. Various low-density dispersion-strengthening additives are used for their synthesis. In this work Ti–Al–Mg lightweight alloy was synthesized using the methods of layer-by-layer combustion and thermal explosion. Relative sample elongation, combustion velocity, and maximum combustion temperature of Ti–Al–Mg system depend on the initial temperature and Mg presence. Phase analysis of the synthesized products with or without mechanical activation of the initial mixture reveals the existence of γ-TiAl, α2-TiAl3, Ti3Al, MgO phases, and γ-TiAl, α2-TiAl3, TiAl2, MgO, and α−Ti phases, respectively. The products synthesized by the thermal explosion mode from mechanically activated mixtures, preliminarily preheated to a temperature above 250 °C, contain the ternary Al18Ti2Mg3 phase. Mg shifts the reaction of Ti and Al to lower temperatures.