Metallic Powders Amorphization by Mechanical Alloying and Subsequent Electrical Sintering

Al-base and Fe-base powders have been amorphized by a high energy milling process in an Attritor miller. Microstructural evolution in powder particles has been analyzed by XRD, DSC. SEMI and TEM. The conventional route of cold pressing and sintering applied to these powders does not result adequate to preserve their amorphous or nanometric character. An additional disadvantage of this route appears during the cold pressing stage, as a consequence of the insufficient green strength of the compacts. due to the high hardness of the milled powders. In order to avoid these difficulties a new consolidation technique, electrical resistance sintering (ERS), has been successfully employed. ERS consolidated compacts have been microstructurally characterized by optical microscopy and XRD, showing that compacts preserve their amorphous and/or nanometric character.