Effects of alloying elements on phase stability in Nb–Si system intermetallics materials

Investigation on the as-cast microstructure of Nb–Nb silicide based multicomponent alloys

“…The compositions of phases in the six alloys are presented in Table 2. Based on the XRD and blocks (a scale of 30w100 mm) possessed a distinctive faceted morphology, being consistent with previous findings in the binary hypereutectic Nb-Si alloys and the ternary Nb-Ti-Si alloys [1,5].…”

“…Nbss, (Nb,Ti) 3 Si, (Nb,Ti) 5 Si 3 and (Ti,Nb) 5 Si 3 have been found in the as-cast microstructure of the N4 alloy based on the XRD pattern in Fig. 1.…”

“…All alloy compositions in this paper are given in atomic percent (at.%) unless stated otherwise. In view of the earlier studies on the effects of adding the group IV metals Ti, Zr and Hf to alloys consisting of Nb-Nb silicide [3][4][5][6], this study is focused on the effect of adding minor amounts of Al, B, Y and Mo on the as-cast microstructures of Nb-22Ti- (15)(16)(17)(18)Si-6Cr-4Hf. The elements Al and Y are selected for improving their oxidation resistance [7][8][9][10].…”

Effect of Gallium on microstructure and mechanical properties of Nb–Si eutectic alloy

“…Chattopadhyay et al reported the formation of Nb ss and a-(NbeMo) 5 Si 3 eutectic suppressing Nb 3 Si phase due to Mo addition [11]. Shiya Qu et al showed that addition of Ti and Hf (having HCP structure) tend to stabilize Nb 3 Si phase, while Cr and Al promote the direct formation of b-Nb 5 Si 3 phase [16]. The increase of primary Nb ss phase and decrease of fine scale eutectic in the microstructure due to Hf addition results an improvement of the in the fracture toughness [15].…”

Microstructure and properties of laser direct deposited CuNi17Al3Fe1.5Cr alloy

“…The chemical composition of different phases is given in Table 1. The long blocky precipitates (position A) are rich in Ni, Ti, Si and Cr and correspond probably to metallic silicides, which are formed as products of the eutectic reaction [12]. Some fine precipitates (position B) distributed near the dendritic branches are rich in Ti and Si, and are probably formed due to the precipitation from the interdendritic solid solution.…”