Mo Fiber Reinforced NiAl Composites Produced by Directional Solidification - Process, Microstructure and Mechanical Properties

摘要

Composites with a eutectic composition NiAl-9at.%Mo were produced by controlled directional solidification (DS) so that refractory metallic Mo fibers were precipitated and aligned in the NiAl matrix parallel to the solidification direction through the eutectic reaction. Such NiAl composites can be used for structural applications at high temperatures (> 1000 ℃), for example as blade material for modern gas turbines. The microstructure of the composites was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The interface fine structure between Mo fiber and NiAl matrix was studied by high resolution TEM (HRTEM). Mechanical properties were measured by tensile tests at 700 ℃ and 1100 ℃. Accordingly, a correlation of the DS parameters, microstructure and mechanical properties was established.