Effect of Deformation by High Pressure Torsion on the Phase Composition and Microhardness of Mechanically Alloyed and Rapidly Quenched Al-Fe alloys

摘要

Aluminium-based Al-Fe alloys with Fe content of 2, 5, 8, 10 and 11 wt. % were prepared by two techniques: rapid quenching (RQ) from the melt at the rate of 10~6 K/s and mechanical alloying (MA) of pure elements in a high-energy planetary ball mill. The structure of the alloys was examined using X-ray diffraction and Moessbauer spectroscopy. It is shown that the crystalline structure refinement and the phase composition of the alloys essentially depend on the techniques used for the sample preparation. Phase transformations by high pressure torsion (HPT) of RQ and MA alloys were studied. The highest supersaturation of Fe in the aluminium-based solid solution can be reached using two subsequent techniques of alloy treatment: RQ and HPT. Microhardness measurements of HPT alloys show the significant stricture heterogeneity of specimens, the dependence of the microhardness on the radius of the pills was found. Phase composition and microhardness at heating were investigated. At the initial step of heating (120-150℃), an increase of microhardness was observed, whereas further heating results in decrease of the microhardness value.