Synthesis of Nb/Nb<SUB>5</SUB>Si<SUB>3</SUB> <I>in-situ</I> Composites by Mechanical Milling and Reactive Spark Plasma Sintering

Abstract

Nbss/Nb5Si3 in-situ composites (Nb–16 mol%Si) for high-temperature structural applications were synthesized by reactive spark plasma sintering (RSPS), mechanically milled (MM) Nb–Si powders. Microstructures were characterized by OM, SEM, XRD and EPMA, and the mechanical properties of the composites were investigated by microhardness and compression tests. This consolidation process can produce the compacts of Nbss/Nb5Si3 in-situ composites having equiaxed grain microstructures and a nearly full density when RSPS is carried out above the melting point of silicon. The RSPS in-situ composites exhibit large compressive ductility at room temperature and considerably high strength at elevated temperatures.