مساهمة في دراسة الخواص الفيزيائية والميكانيكية لسبائك ثنائية (نحاس ــــ ألمنيوم)

Résumé: In order to determine the factors leading to the increase of the porosity and these reflections on the mechanical properties in particular the hardness; we used the powder pressure technique to prepare samples of copper-aluminum alloys with the concentrations of 0, 5, 11, 14 and 18% Al, using a pressure of 12.5 MPa. The samples were treated under vacuum of 5.10-3 mbar at 700, 800, 900 and 1000°C. X-ray diffraction patterns showed the appearance of the α phase in the 5% samples and its predominance in the 11% samples. The diagrams also showed the beginning of the germination of the  phase in these late samples and continues to grow and replaces the α phase with the increase in the concentration of aluminum from 11% to 14% and with higher rate for 18% Al samples. Measurements show the increase in average grain size with increasing aluminum concentration. The hardness measurement results showed that it increases tenfold from 69.8 to 698.8 kg/cm2 due to the sintering temperature, and increases with increasing aluminum concentration. Significant hardness values were recorded on samples with  phase; the highest, 698.8 kg/cm2, was found for the 18% Al samples treated at 1000°C. However, the 14% sample treated at 1000°C showed a value of 615.2 kg/cm2; We found that in a single-phase domain, hardness increases with decreasing of grain size.

Publié dans la revue: