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利用真空非自耗电弧炉制备了不同Al含量的Nb-21Ti-4C(βNb-Ti)合金,研究了Al元素含量变化对Nb-21Ti-4C合金组织和晶格常数的影响。研究表明:铸态条件下合金由枝晶生长的Nb基固溶体(Nbss),碳化物((Nb,Ti)C),Nb3Al和枝晶间Nbss/MC共晶组织构成;Al元素部分固溶进入Nbss和MC中,随着Al含量增加,以Nb3Al相生长在Nbss内部。Al元素含量增加,使得Nbss枝晶先变大后变小。1100℃,24h热处理后,Nbss内部析出针状或片状碳化物和Nb3Al,导致Nbss晶格常数增大;枝晶间碳化物内部Nbss进一步长大,Nb原子的析出和Al元素固溶含量变化导致碳化物晶格常数改变。
The Nb-21Ti-4C (βNb-Ti) alloys with different Al contents were prepared by vacuum non-consumable electric arc furnace. The effects of Al content on the microstructure and lattice constants of Nb-21Ti-4C alloy were investigated. The results show that the as-cast alloy consists of Nb-based solid solution (Nbss), carbide ((Nb, Ti) C), Nb3Al and Nbss / MC eutectic between dendrites. In MC, as the Al content increases, the Nb3Al phase grows inside the Nbss. Al element content increases, making Nbss dendrite first become smaller and smaller. After heat treatment at 1100 ℃ for 24h, needle-shaped or flaky carbides and Nb3Al precipitated in Nbss, which led to the increase of the lattice constant of Nbss, the further growth of Nbss in the interdendritic carbide, the precipitation of Nb atoms and the change of Al-element solid solution Resulting in changes in the lattice constant of the carbide.