Transformation of the structure of the sintered aluminum bronze with the free forging

Sintered materials exhibit some reduction in mechanical properties due to residual porosity. To eliminate the defects that arise during sintering, a pre-compacting operation combined with shaping is applied. Because the pressing force is limited, it is possible to increase the density of the compacted sample only by decreasing its area, increasing the load on the tool, or by heating the workpiece to a temperature markedly decreasing the strength of the pressed material. It is possible to oxidize the material in open pores. After the collapse of the pores, further deformation of the material is not possible, and the values of the tested material may not be sufficient for a substantial study of the structure in the entire volume of the sintered material.When the samples are free of sediment, the amount of superimposed deformation is limited only by the power of the press tool, because during the sedimentation of the samples, the area of their cross sections increases, and the deformation hardening of the material. The material flow is carried out by shifting along the planes of the maximum shearing stresses. In the course of the work, the influence of temperature on the behavior of single-phase cu-15 at. % al and two-phase cu-24 at. % al compositions on the behavior of a special bronze was studied. It was established that the sediment of samples from sintered alloys without destruction can reach 30 %. The increase in the pressing temperature leads to a significant decrease in the working pressure, but a noticeable compaction of the material is observed only at a temperature above 500 °С, when the deformation begins to be distributed uniformly over the volume of the samples.