Mechanical Alloying Processing with Applications to Structural Materials
Final rept. Aug 94-Mar 98
MICHIGAN TECHNOLOGICAL UNIV HOUGHTON DEPT OF METALLURGICAL ENGINEERING
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Relationships among the synthesis, processing, structure and properties of materials generated through mechanical alloying MA or mechanosynthesis are described. Several materials classes cermets, particulate metal matrix composites MMC, and tungsten heavy alloys WHA have been produced, and their properties and structures evaluated. Niobium carbide and tungsten, carbide cermets can be conveniently generated either through room temperature synthesis NbC cermets or by room temperature milling followed by elevated temperature exposure WC cermets. Cermet microstructures following consolidation are fine, and the materials demonstrate exceptional hardnesses albeit their fracture toughnesses are generally low. Al based MMC can be synthesized similarly. The composites we have studied utilize aluminum carbide as a reinforcement. The yield strengths of these MMC are approximately twice those of high strength aerospace Al alloys. Noncrystalline WHA can be generated via MA. During consolidation, these alloys are prone to crystallization. Nonetheless, because of their fine structure the crystalline products manifest high hardnesses relative to conventional WHA. Current efforts are focusing on retaining the noncrystalline phase during consolidation so as to produce materials having particularly desirable mechanical properties.
- Ceramics, Refractories and Glass
- Laminates and Composite Materials