CHARACTERIZATION OF RAPIDLY SOLIDIFIED AND MECHANICALLY ALLOYED Al-Fe-Ce POWDERS.

Mechanical alloying of rapidly solidified Al-8. 4% Fe-3. 4% powders has been studied. Various powder characterization techniques have been used to follow the mechanical alloying process. An organic surfactant has been added to maintain a balance between cold welding and fracturing. Differential Scanning Calorimetry (DSC) measurements have indicated that most of the surfactant is incorporated into the matrix during an intermediate stage. In spite of this fact, cold welding continues to be inhibited until the processing reaches a steady-state. The achievement of steady-state processing conditions depends on the initial powder size distribution, the amount of surfactant added and the processing time. At steady state the particles have a uniform size distribution, a saturation hardness, an equiaxed shape and a composite structure. From the characterization studies, a steady-state processing time of between 120 and 240 minutes has been determined. Mass Spectroscopy Analysis (MSA) experiments have been conducted to determine the degassing conditions for further thermomechanical processing.