Nb-Si基合金的凝固行为模拟

The Solidificational Simulation of Nb- Si Based Alloy

Nb-si基合金具有高熔点、密度适中和优良的室温和高温力学性能，成为镍基高温合金的替代材料．为了研究不同成分合金的组织变化规律，模拟了Nb-Si合金的凝固行为．随着Si所占比例从10％增加到50％的过程中，初生相最开始是Nbss（铌基固溶体），当Si的比例为20％～30％时初生相转变为Nb3Si，当Si含量为50％时初生相转变为Nb5Si3．共晶组织最开始为Nbss＋Nb3Si，随着Si比例增加到30％，而转变为Nb5Si3＋Nb3Si，Si比例继续增加到50％时，共晶组织为Nb5Si3＋NbSi2．

As a promising candidate of Ni based high temperature materials, Nb-Si based alloy possesses high melting point, relatively tow density and excellent high temperature strength. The solidificational simulations of Nb-Si based alloy were studied in order to study the microstructure. The primary Nbss was presented firstly when the Si concentration was 10%, and the primary Nb5Si3 was presented when the Si concentration varied from 20% to 30%, and the primary Nb5Si3 was present when the Si concentration was higher than 50%. The eutectic colonies was composed of Nbss and Nb3Si firstly, and the eutectic colonies was composed of Nb5 Si3 and Nb3Si when the Si concentration is 30%, and the eutectic colonies was composed of Nb5Si3and NbSi2 when the Si concentra-tion is higher than 50%.