Aluminum alloy matrix composites with discontinuous fibers oriented uniaxially by electrostatic method

An electrostatic method for fabricating uniaxially oriented ceramic discontinuous fiber preforms has been developed. Alumina short fibers suspended in an insulating liquid (Freon R-113) are aligned to form long agglomerates and sedimented to form a preform in the DC field. SiC whiskers, on the other hand, form into similar agglomerates in the AC field. A fabricated preform is incorpolated into an aluminum alloy JIS AC1A melt by squeeze casting. This FRM contains uniaxially aligned short fibers or whiskers and is free from defects. Uniaxially oriented FRM have higher bending strength than FRM with 2-dimensional and 3-dimensionally random orientations at the same volume fraction of short fibers or whiskers. Uniaxially oriented SiC composits have the highest bending strength 1.07GPa at room temperature, showing a great advantage of using uniaxially oriented preforms.