THE BEHAVIOR OF SINTERED ALUMINUM BRONZE DURING PRESSURE TREATMENT

Sintered aluminum bronzes are widely used in mechanical engineering. However, they are inferior in strength to their cast analogs.

It is known that sintered materials demonstrate the decrease in mechanical properties due to the residual porosity that occurs during the sintering process. To eliminate the previously mentioned deficiencies, the post-compaction operation combined with shaping is used.

The application of additional compaction of sintered materials is associated with certain difficulties since the density of the pressed sample is increased only by reducing its area with the increment of the load on a tool, or by heating the workpiece up to the temperature noticeably reducing the strength of the pressed material. In such a case, it is possible to oxidize the material in open pores. After the collapse of the pores, further material deformation is impossible and the value of tested deformation can be insufficient for the substantial study of the structure within the entire volume of sintered material.

In the present work, the influence of temperature on the behavior of single-phase Cu-15 at. % Al and two-phase Cu-24 at. % Al compositions during the compression of sintered bronze is studied.

It is determined that the transformation of the structure of sintered bronzes should be carried out at the temperature not lower than 500 °C when the deformation begins to be distributed relatively uniformly within the volume of the samples.

However, it is recommended to get rid of open porosity in advance by processing at low temperatures. The degree of deformation should not exceed 30 % in height. The exceeding of this deformation value leads to the sample destruction.

It is shown that during the high-temperature upsetting, the initial structure of sintered bronze is destroyed by means of grinding that increases the strength of the material.