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

Effect of Mg addition on microstructural, mechanical and environmental properties of Nb–Si eutectic composite

“…Contrary to the effect of group 3B elements like Al and Ga, Mg which is a 2A element in periodic table does not alter the stability of Nb 3 Si phase [15,16]. more to primary phase.…”

“…The precision lattice parameters of BCC Nb solid solution and tetragonal Nb 3 Si phase in Mg added ternary alloy are determined to be: a¼ 3.32770.001Å for BCC phase and a¼ 10.28970.001Å; c¼ 5.16070.001Å for Nb 3 Si. The corresponding lattice parameters for the phases in binary alloy are reported to be a¼3.30970.001Å for BCC Nb and a¼10.21670.002Å; c¼ 5.18670.001Å for Nb 3 Si [15].…”

“…The volume fraction of the primary dendritic phase for each alloy was measured following the procedure prescribed in ASTM E562 [19]. The primary phase fraction in the ternary alloy containing Mg is 3175% while a value of 22 74% is obtained for the binary alloy [15]. In order to determine the structure of the individual phases present in the microstructure transmission electron microscopic investigation has been carried out.…”

“…However, the main obstacles for its development are its low fracture toughness and poor oxidation resistance [1,2]. In order to overcome these limitations, several alloying additions have been attempted [3][4][5][6][7][8][9][10][11][12][13][14][15]. These affect the crystal structure, melting temperature, phase distribution and microstructure.…”

“…Al addition has shown significant improvement in mechanical and oxidation properties of Nb-Si alloys [15]. There are several reports on small addition of elements such as Ga, Sn, Ge and B in Nb-Si eutectic alloys [4,9,11,15,16]. Most of these yield better density and multifold improvement in mechanical properties.…”