Accession Number : ADA306660

Title :   The Effect of Thermomechanical Processing on the Tensile Properties and Microstructure of A 6061 Al-Al2O3 Metal Matrix Composite.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Ballou, Michael A.

PDF Url : ADA306660

Report Date : DEC 1995

Pagination or Media Count : 80

Abstract : This work includes a comprehensive analysis of the effect of thermomechanical processing (TMP) history on the microstructure and properties of 10 and 20 volume percent 6061 Al-Al2O3 discontinuous metal matrix composites (MMCs). Materials in which cold drawing operations were included in the TMP demonstrated increased ductilities for a given strength level when compared to samples which were processed by hot extrusion only. Microstructural analysis provided clear evidence of the absence of damage to reinforcing particles during TMP and of load transfer to these particles during subsequent straining. Failure during tension testing resulted from the ductile tearing of the matrix as voids initiated by the cracking of reinforcement particles, joined together. A distinct microstructural difference related to processing history was the development of a strongly fibered particle distribution in materials experiencing low temperature drawing operations. In order to conduct an analysis of the mechanisms by which the particles are redistributed and reoriented during processing, a channel compression die was constructed which allowed processing to be simulated by compressive straining on a mechanical testing machine. This allowed careful control of the processing parameters. An analysis of the effects of processing temperature on particle redistribution and reorientation was conducted.

Descriptors :   *THERMOMECHANICS, *MICROSTRUCTURE, *TENSILE PROPERTIES, *METAL MATRIX COMPOSITES, *ALUMINUM OXIDES, TEST AND EVALUATION, COMPRESSION, TEMPERATURE, LOW TEMPERATURE, DAMAGE, DISTRIBUTION, PARAMETERS, PROCESSING, STRUCTURAL ANALYSIS, CRACKS, THESES, EXTRUSION, NUCLEATION, DIES, PARTICLES, TENSION, STRENGTH(GENERAL), DUCTILITY, TRANSFER, CHANNELS, REINFORCING MATERIALS, TEARING, COLD DRAWING.

Subject Categories : Inorganic Chemistry
      Laminates and Composite Materials
      Properties of Metals and Alloys
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE