Abstract
Two alloys of composition Al-Mo(3; 5) at.% and Al-Mn(3; 5) at.% were studied in the form of compacted cuts of rapid solidification ribbons. The structure of samples was composed of fcc α-Al solid solution oversaturated with Mo and Mn, intermetallic Al₁₂Mo and Al₆Mn phases, all in ultrafine submicron grain size. The kinetics of structural changes and their effect on mechanical properties were described as a function of annealing temperature and time. The discrete RS particles (chopped ribbons) were compacted into simple structural profiles using conventional and relatively inexpensive direct extrusion method. All compacted profiles exhibited similar structure as precursor materials, incl. even grain size. Almost theoretical density with no identified porosity and gas entrapment was achieved. The extruded profiles were extremely thermally stable; no structural changes were detected even after annealing at 300 °C for 24 h. The best mechanical properties were obtained for compacted RS AlMo5 ribbons: their UTS at room temperature exceeded 385 MPa at 5 % elongation to fracture. UTS at 300 °C/24 h regularly exceeded 375 MPa what is 5 times higher than UTS of conventionally used Al alloys. Young’s modulus (E) of extruded compact at RT was 90 GPa what means an increase of more than 25 % in E/ρ compared with standard Al.

Key words
aluminium, mechanical properties, melt-spinning, rapid solidification, thermal stability

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