Structural evaluation of Al-4Mn-5Al_2O_3 (wt-%) nanocomposite produced by mechanical-thermal synthesis and powder technology methods

摘要

Production of Al-5Al_2O_3-4Mn (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.