Mechanical alloying in compositions iron–titanium–carbon (diamond)

Abstract

X-ray diffraction analysis, scanning electron microscopy and M¨ossbauer spectroscopy have been applied to the study of Fe-xTi (x=20–40 wt.%), Fe/xTi-diamond and Fe–Ti–C powders structure formation under the conditions of an AGO-2 planetary ball mill. It has been shown that metals with high melting points and limited solubility under high-energy mechanical action for 20 min interact to form an alloy of nanostructured iron and grain-boundary phases similar to solid solutions of Fe(Ti), Ti(Fe) and FeTi with a total content of 22–24 %. In the Fe-20wt.%Ti composition, titanium reaches an X-ray amorphous state, and when the titanium content is above 20 wt.% 𝛼-Ti crystalline phase remains in an amount of 5–10 wt.%. When the Fe/xTi-diamond mixture is mechanically activated, composite particles with a metal matrix structure with a diamond size of 0.3–1.5 𝜇m are formed. It has been established titanium accelerates the process of grain-boundary and volumetric interaction of iron with diamond and titanium carbide. In the powder compositions under study, a solid solution is formed based on iron and TiC, Fe3C compounds with their total content: Fe/40 wt.%Ti-diamond up to 62%; Fe/TiC up to 34%. Under similar conditions in a diamond-iron mixture, the grain-boundary phases of the solid solution do not exceed 26%. The formation of graphite has not detected by X-ray diffraction.