Structural evaluation of Al–4Mn–5Al 2 O 3 (wt-%) nanocomposite produced by mechanical–thermal synthesis and powder technology methods

Production of Al–5Al₂O₃–4Mn (wt-%) nanocomposite via ball milling and subsequent heat treating of the milled samples was investigated. Duration of milling time was considered as a variable by which microstructure of the matrix is influenced. The structural evaluation of samples was performed by means of X-ray diffraction, differential thermal analysis, scanning electron microscopy and hardness measurement. The steady state time was found to be 3–7 h, prolonged milling time that had no effect on melting point, hardness, morphology and integral breadth of X-ray reflections of milled powders. A maximum hardness of 275 HV was obtained due to the nanocrystalline structure of Al matrix and a uniform dispersion of nano- and submicron second phase particles.