THE STRUCTURE OF THE Al₇₀Cu₃₀ ALLOY AFTER CRYSTALLIZATION FROM THE LIQUID PHASE AT EXTREME PRESSURES

A comparative study of Al₇₀Cu₃₀ binary alloy samples obtained from the liquid phase at normal and high pressures of 3–5, 7, 8, and 10 GPa was performed using metallographic and X-ray diffraction analyses using electron microscopy. The melt temperature before quenching is 1100 and 1300 °C, the cooling rate is ~1000 °C/s. Two phases were revealed in the structure of all the obtained samples: α-Al (cubic, cF4/1) and Al₂Cu (tetra, tI12/2). When solidified under a pressure of 3–4 GPa, the structure is crushed, compared with the original ingot obtained at normal pressure, the morphology of the structural components of the alloy changes. Changing the pressure from 5 to 8 GPa leads to additional refinement of the alloy microstructure. Crystallization occurs with the formation of solid solutions with a high copper content in aluminum. A pressure of 10 GPa promotes the formation of quasi-entectic in the alloy. The selected thermobaric action modes lead to an increase in the hardness of the samples, which is due to the refinement of the microstructure and the formation of solid solutions in the alloy.

extreme effects, microstructure, microhardness, aluminum-copper alloy, high pressure, electron microscopy, melt