Macroheterogeneous composites based on AI65C020CU15 quasicrystal alloy

Abstract

Purpose. Quasicrystal alloys show promise as a way to create composite materials with unique properties. The search for new compositions and fabrication technologies of composites is needed to enhance their performance life. Methodology. Macroheterogeneous composites reinforced by macrogranules made of Al6sCo20Cu15 quasicrystal alloy were fabricated by pressure-free infiltration at 670 °С during 2 0 .3 0 minutes. АМг30 metal alloy wasused as binder. The composites’ structure was investigated by the methods of metallography, X-Ray analysis and X-Ray microanalysis. Findings. It is shown that the method of pressure-free infiltration allows the practically defect-free structure of АМг30/(Al65Co2oCul5) composite material to be achieved. The changes in the phase composition of the composites affected by temperature-and-time infiltration cycle were determined. The structure formation of interfaces between the filler and the binder is established to proceed under dissolution-and-diffusion mechanism. During the infiltration quasicrystal D-phase dissolves in the infiltrating metal at much higher rate compared to that of crystal phases. This would account for relative content of the quasicrystals in the composites’ structure at the level of not less than 25 pct. Originality. For the first time the method of pressure-free infiltration was applied to fabricate macroheterogeneous composite materials reinforced by quasicrystal filler macrogranules. The temperature-and-time process variables were determined. Al6sCo20Cu15 quasicrystal alloy as filler and АМг30 alloy as metal binder are shown to be promising structural components of the macroheterogeneous composites. The peculiarities in structure formation of interfaces between the filler and the binder were studied. Practical value. For the first time Al6sCo20Cu15 quasicrystal granules sized from 0,25 to 1,5 mm were used to reinforce macroheterogeneous composite materials fabricated by pressure-free infiltration method. Quasicrystal filler granules showing low friction factor and high resistance to corrosion allow performance life of the composites to prolong. As a result, the suggested composites may be used to strengthen or repair friction units of internal combustion engines, turbine compressors, face seals friction couples of diesel pumps, cylinders and other parts of motor transport.