近快速凝固條件下Ni-50%Sc金屬間化合物韌脆性

近快速凝固條件下Ni-50%Sc金屬間化合物韌脆性Ductility of near rapidly solidified Ni-50%Sc intermetallics

通過真空電弧熔煉水冷銅模吸鑄法制備Ni-50%Sc合金，用XRD和EDS分析合金的相組成，研究其金屬間化合物的韌脆性。結果表明：凝固組織為B2-NiScp+(NiSc+Ni2Sc)e，其中共晶組織分布在晶界與枝晶臂之間。在外力作用下的受力鏈“B2p-晶界1-Ni2Sce-晶界2-B2e-晶界2-Ni2Scp-晶界3-B2e”中，Ni2Sce和與其相連的晶界是裂紋產生的區域，而B2-NiSc是塑性較好、在外力作用下可以發生較大變形的金屬間化合物。

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 Ni2Sceutectic and grain boundary connected with Ni2Sceutectic are the nucleation region of the crack among force chain of B2primary-grain boundary1-Ni2Sceutectic-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 functional theory. Intermetallic NiSc with B2-structure is a ductile phase, which experiences large deformation under external force.

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