Mechanical Alloying of Iron–Titanium–Carbon (Diamond) Compositions

Abstract

Using methods of X-ray structural analysis, scanning electron microscopy, and Mössbauer spectroscopy, the features of the structure formation in powder systems Fe–Ti, Fe/Ti–diamond and Fe–Ti–C during mechanical alloying under the conditions of the planetary ball mill AGO-2 (energy intensity 7 W/g) were studied. It is shown that titanium and iron with limited mutual solubility under high-energy mechanical impact with a duration of 20 min interact to form an alloy of nanostructured iron and grain boundary phases of the type solid solutions Fe(Ti), Ti(Fe), and FeTi with a total 22–24\(\%\) content. In the composition of Fe-20\(\%\) Ti, titanium reaches an X-ray amorphous state, and at a titanium content above 20 wt \(\%\), the crystalline phase \(\alpha\)-Ti is preserved in the amount of 5–10 wt \(\%\). During mechanical activation of the Fe/Ti–diamond mixture, composite particles are formed with a size in the range of 2–12 \(\mu\)m, with a metal matrix structure with a diamond particle size of 0.3–1.5 \(\mu\)m. It has been established that titanium accelerates the process of grain boundary and bulk interaction of iron with diamond and titanium carbide. In the studied powder compositions, a solid solution based on iron and TiC, Fe\({}_{3}\)C compounds is formed with their total content: Fe/40\(\%\), Ti–diamond up to 62\(\%\); Fe/TiC up to 34\(\%\). Under similar conditions in the diamond–iron mixture, grain boundary phases of the solid solution do not exceed 26\(\%\). The formation of graphite has not been detected by X-ray diffraction.