Developing and Understanding the High Temperature Behavior of Niobium Aluminideand Niobium Aluminide Composites

摘要

The present three year study has sought to understand the potential for, andlimitations to, development of high temperature structural materials based on niobium aluminide and transition metal beryllide intermetallic compounds. Beginning with a broad examination of some important properties, this project has identified promising areas for research and culminates with significant additions to the body of knowledge on both of these classes of materials. During the first two years of this program, significant effort was concentrated on securing a source and establishing processing routes for the materials under consideration. This was necessarily accompanied by the development and use of scoping techniques for initial characterization of the candidate materials and processes. Such techniques need to be rapid and informative tests which are forgiving of sample imperfections, so that a few parameters of interest of a large number of sample materials can be easily compared. In this study the techniques based upon high temperature micro-indentation were chosen to rank the various static and time-dependent mechanical properties, and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) was used for microstructural and chemical evaluation.