Characteristics of Al-B mixed powders produced by a high energy planetary ball mill

The mechanical alloying process of Al–B system mixed powders under a surging mode of a high energy planetary ball mill was investigated by means of microscopic observation, X-ray diffraction and hardness measurement. In the X-ray diffraction pattern, each Al peak shifted to high angle side with increasing the milling time. These peak shifts correspond to decrease in the lattice parameter of Al. The supersaturated solute B atoms take the substitutional positions in fcc Al cluster and resulted in lattice construction of α–Al. B atoms about 13 atomic percent solubled in the solid Al during mechanical alloying of Al–B mixed powders. The average grain size of Al–30at%B mixed powders milled for 345.6 ks was about 15nm. For the reason of solid solution hardening by B solubilities to solid Al, grain refinement of α–Al phase and work hardening during mechanical alloying, maximum hardness of Al–20at%B and Al–30at%B mixed powders was more than 400 HV.