Structure and properties of alloys based on electroerosive brass powder LS58-3 obtained in distilled water

Abstract

   The purpose of this work was to study the microstructure and physico-mechanical properties of alloy blanks based on electroerosive powder brass of the LS58-3 brand obtained in distilled water.   Methods. To carry out the planned research, waste of the LS58-3 alloy was selected. Distilled water was used as the working fluid. In an experimental patented installation for producing powders, waste LS58-3 alloy was dispersed in distilled water with a load mass of 300 g. The following modes were used: capacitor capacity 45–65 μF; voltage at the electrodes from 150–200 V; pulse repetition rate 50–100 Hz. The preparation of new alloy blanks was carried out using an SPS 25-10 electric spark plasma sintering installation (ThermalTechnology, USA). The microstructure of new alloy workpieces was studied using an electron-ion scanning (raster) microscope QUANTA 600 FEG (Netherlands). The study of the porosity of workpieces of new alloys was carried out using an optical inverted microscope OLYMPUS GX51 (Japan). The study of microhardness of workpieces of new alloys was carried out using an automated microhardness tester AFFRI DM-8 (Vickers).   Results. Analysis of the microstructure showed that the sample has a fine-grained structure and a homogeneous surface. According to the obtained porosity analysis results, the sample has less than 1% pores, which is achieved thanks to the technology of spark plasma sintering of the powder. Analysis of the microhardness of the sample showed a significant increase in microhardness, which is explained by the presence of high-hard particles formed during quenching of metal vapor in the working fluid during dispersion.   Conclusion. The use of spark plasma sintering technology for electroerosive brass makes it possible to obtain blanks of new alloys with a practically non-porous structure, which leads to an increase in the hardness of the resulting blanks. The results of the conducted studies make it possible to recommend the use of the resulting powder as a starting material for the production of alloy blanks and to expand the scope of their practical application.