The influence of alloying elements on phase constitution and microstructure of Mo3M2Si3 (M=Cr, Ti, Nb, Ni, or Co)

The microstructure and phase constitution of highly alloyed Mo5Si3 have been investigated. As cast alloys Mo3M2Si3, where M=Cr, Ti, Nb, Ni or Co, were annealed for 120 h and subsequently characterised by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and powder X-ray diffraction (XRD). With M=Cr, Ti, or Nb, EDS and XRD experiments suggested the matrix phase to consist of (Mo, M)5Si3. However, when M=Ni or Co the matrix phase consisted of MoNiSi and CoMoSi, respectively, with Mo5Si3 as a minor phase. The solubility of Ni and Co in Mo5Si3 were in the order of 2–3 at.%.