The Research On The Structure And Morphology Transformation Rule Of Immiscible Al-Pb Binary System In The Process Of Ball Milling And Sintering

In this paper, we use the scanning electron microscope to analysis the particles and structuremorphology evolution characteristic of immiscible Al-Pb binary system in the process ofmechanical alloying and sintering, and use the X-ray diffraction to analysis the change rule ofthe grain size and the lattice constant of the phase at all stages.The results show that the mechanical milling only leads to the grain size decreasing tonanometer level. Even adding Cu element, the product of the ball-milling does not contain thesecond phase. As the time of ball milling increases, the microstructure in the matrix changesfrom the mutually agglomerate Al-Pb composite layered structure to the morphology ofPb-phase dispersed distributed in the Al matrix. In addition, the change rule of the latticeconstant is determined by the two kinds of effect, the welding and comminuting. The weldingdominates, distortion quantity decreases, lattice constant decrease. The comminuting dominates,distortion quantity increases, lattice constant increases.The immiscible powder obtained by ball-milling will be pressed and sintered. As thetemperature of sintering increases, the Pb-phase changes from rotated the reticular morphologywhich distributes along the particle interface to the morphology of dispersed distributed in the Almatrix. In addition, the organization which added Cu element contains CuAl2phase andcopper-rich phase. The sintering leads to the grain size increasing, and the grain size still keepsin the nano-scale. In the process of sintering, the change rule of the lattice constant is determinedby the weakening of the welding and comminuting. The weakening of the welding is strong,distortion quantity increases, lattice constant increases. The weakening of the comminuting isstrong, distortion quantity decreases, lattice constant decreases.