• Krzywińska, Sylwia
• Oleszak, Dariusz

Abstract

Commercial crystalline AA4048 powders and mechanically alloyed amorphous Al60Nb40 (at.%) powders were used for fabrication of crystalline-amorphous composites containing 10, 20 and 30 vol% of amorphous phase. High pressure high temperature technique was used for powders compaction. The applied pressure was 7.7 GPa and temperature was in the range 600–1000 _C. The powders and bulk samples were characterized by structural investigations (X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, X-ray fluorescence spectroscopy), hardness and microhardness tests and measurements of density. The obtained sinters revealed relative density above 98.7%. The amorphous component was observed as agglomerates or as single particles surrounding the grains of crystalline AA4048 phase. The crystallization of amorphous phase was not observed. Simultaneously, up to 2.5 wt % of Fe was detected as impurity from milling media. Significant increase of hardness was observed, from 226 to 288HB, resulting from the presence of amorphous component which prevent from cracks propagation during deformation.

Topics

• density
• amorphous
• grain
• phase
• scanning electron microscopy
• x-ray diffraction
• grinding
• crack
• milling
• composite
• hardness
• crystallization
• fluorescence spectroscopy
• X-ray fluorescence spectroscopy