“…For various purpose, Dy, Hf, Ti, Sn, Cr, Al, Mo, W, Ge, Ta, V, B, Fe and some other elements have been separately added in to Nb-Sibased composites [8][9][10][11][12][13][14][15], and it reported that the adding Zr and Mg at the same time can make significant impact to the microstructure of Nb-18Si binary alloy [16]. The effect of macro alloying element Zr and micro alloying element Mg on the microstructure, phases and fracture toughness at room temperature of Nb-Si based multiple alloy have been studied in this investigation.…”