|VODĚROVÁ Milena||VŠCHT Praha|
|Spoluautoři NOVÁK Pavel, MICHALCOVÁ Alena, VOJTĚCH Dalibor|
Aluminium alloys prepared by rapid solidification are perspective materials for many special applications. In this work, microstructure of three rapidly solidified aluminium alloys has been studied and compared. Studied were alloys of following chemical composition: Al-11Fe, Al-7Fe-4Ni and Al-7Fe-4Cr (wt. %). Nickel and chromium as alloying elements were chosen due to the low solubility and diffusivity in aluminium matrix which improves mechanical properties and thermal stability at elevated temperatures. Samples in the form of thin ribbons were prepared by melt spinning technique. Microstructure of investigated alloys was studied by scanning electron microscopy (SEM). Phase composition was determined by x- ray diffraction (XRD). Vickers hardness (HV 0,005) was measured to estimate mechanical properties as well as thermal stability after two types of annealing: 1 hour annealing at 100-600 °C and long term annealing (500 h) at 300 and 400 °C. Rapidly solidified alloys consist predominantly of supersaturated solid solution of alloying elements in aluminium on the wheel side and fine particles of intermetallic phases on the free side. Material hardness decreases with higher increasing temperature. Chromium improves the thermal stability more than nickel.