Synthesis of Nb/Nb5Si3 in-situ composites by mechanical milling and reactive spark plasma sintering

Nb-ss/Nb5Si3 in-situ composites (Nb-16 mol%Si) for high-temperature structu ral applications were synthesized by reactive spark plasma sintering (RSPS) , mechanically milled (MM) Nb-Si powders. Microstructures were characterize d by OM, SEM, XRD and EPMA, and the mechanical properties of the composites were investigated by microhardness and compression tests. This consolidati on process can produce the compacts of Nb-ss/Nb5Si3 in-situ composites havi ng equiaxed grain microstructures and a nearly full density when RSPS is ca rried out above the melting point of silicon. The RSPS in-situ composites e xhibit large compressive ductility at room temperature and considerably hig h strength at elevated temperatures.