Structure, Properties, and Processing of Two-Phase Crystalline-Amorphous W-Based Alloys

摘要

The thermal stability and crystallization behavior of noncrystalline W-Ni alloys have been investigated. These materials are generated by the mechanical alloying process. The powders so produced consist of a noncrystalline matrix containing a dispersion of nanometer-sized crystalline W particles. We find that the crystallization temperatures of these materials are tied closely to the W content in the amorphous phase. This composition can be varied by alterations in either the overall W content of the alloy or the mechanical alloying time. Thermal stability studies - monitored by differential scanning calorimetry, x-ray diffraction, and transmission electron microscopy - have identified promising thermally stable noncrystalline W compositions. Consolidation of mechanically alloyed noncrystalline powders absent their crystallization is difficult. Several promising consolidation routes have been identified. These may permit production of fully dense noncrystalline powders in bulk form. Such material may have potential as kinetic energy penetrators.