中文摘要：

通过真空电弧熔炼水冷铜模吸铸法制备Ni-50%Sc合金,用XRD和EDS分析合金的相组成,研究其金属间化合物的韧脆性。结果表明：凝固组织为B2-NiSc_p＋（NiSc＋Ni_2Sc）_e,其中共晶组织分布在晶界与枝晶臂之间。在外力作用下的受力链＂B2_p-晶界_1-Ni_2Sc_e-晶界_2-B2_e-晶界_2-Ni_2Sc_p-晶界_3-B2_e＂中,Ni_2Sc_e和与其相连的晶界是裂纹产生的区域,而B2-NiSc是塑性较好、在外力作用下可以发生较大变形的金属间化合物。

英文摘要：

Ni-50%Sc alloy was prepared with a vacuum arc smelting and water cooled copper mold suction-casting machine. XRD was used to identify phase microstructural components, and the composition of each phase was analyzed with EDS. The ductility of intermetallics was studied. The results show that the solidification structure is B2-NiScprimary and （Ni2Sc＋NiSc）eutectic, and the eutectic is distributed between the grain boundaries and dendrite arms. The Ni2Sceutectie and grain boundary connected with Ni2Sceutectic are the nucleation region of the crack among force chain of B2primary-grain boundaryl-Ni2Sceutectio-grain boundarY2-B2eutectic-Ni2Sceutectic-grain boundary3-B2primary- NiSc plasticity is better than Ni2Sc by using the first-principles plane-wave pseudo-potential method based on density ftmctional theory. Intermetallic NiSc with B2-structure is a ductile phase, which experiences large deformation under external force.