Influence of sintering temperature on microstructures of Nb/Nb5Si3 in situ composites synthesized by spark plasma sintering

Abstract: Taking the use of Nb and Si elemental powders as raw materials, Nb/Nb5Si3 composites were successfully fabricated by a spark plasma sintering (SPS) technology. The influence of sintering temperatures on microstructures of the synthesized composites was mainly investigated. The results show that there exists a critical sintering temperature T c (1400°C) in the synthesis of Nb/Nb5Si3 composites by SPS technology. When sintering temperature is lower than T c, an intermediate Nb3Si phase is produced in the fabricated samples. Moreover, the relative density of the samples is lower. Only if the sintering temperature is higher than T c, the intermediate Nb3Si phase is thoroughly eliminated, Nb particles become a finer size and desirable Nb/Nb5Si3 composites up to 99.59% theoretic density are achieved. [Copyright &y& Elsevier]