Al-Cr P/M合金の組織と機械的性質に及ぼすメカニカルグライディングの影響

抄録

The influence of mechanical grinding on structure of the atomized Al-2%Cr and Al-4%Cr powders was studied by using SEM, EPMA and X-Ray diffraction. Tensile properties of extrusions prepated from the mechanically ground powders were compared to those of extrusions prepared from the atomized powders. Mechanical grinding was carried out for various periods from 20 to 300min by using an attritor type ball mill. Chromium dissolves in aluminum over the solubility limit at room temperature by the atomization treatment. Very fine particles are precipitated from the matrix phase when grinding time is over 180min, but these particles can not be identified by X-Ray diffraction method. The lattice parameter of matrix phase increases with increasing grinding time. In the extrusions of the mechanically ground powders, but the precipitates are observed, but they are not observed in the extrusions of the atomized powders. No change in the lattice parameter is not observed before and after extrusion of the atomized powder, but the lattice parameter increases during extrusion of the mechanically ground powder. Tensile strength of the extrusions of the mechanically ground powders is higher than that of the atomized powders, and elongation is in the reversed relation.