材料期刊网

利用“团簇+连接原子”结构模型研究了典型低弹bcc β-Ti固溶体合金的成分特征. 对现有低弹β-Ti固溶体合金的成分分析表明它们均满足团簇式[CN14团簇](连接原子)_x. 根据该式, 设计了Ti-Mo-Nb-Zr系列合金 [MoTi₁₄]Ti (质量分数表达时为Ti-11.8Mo), [MoTi₁₄]Nb (Ti-11.2Mo-10.8Nb), [MoTi₁₄]Nb₂ (Ti-10.1Mo-19.5Nb)和[Mo(Ti₁₃Zr)]Nb₂ (Ti-9.2Zr-9.6Mo-18.7Nb), 并采用Cu模吸铸快冷技术制备直径为3和6 mm的合金棒. 结果表明, 吸铸制备的合金均为bcc结构; 当连接原子由Ti变成更低弹的Nb时, 合金弹性模量降低; 低弹Zr替代Ti进一步降低了合金的弹性模量, [Mo(Ti₁₃Zr)]Nb₂ 合金的弹性模量E=72 GPa. 铸态样品经过固溶和水淬处理后弹性模量降低.

The composition characteristics of typical bcc β-Ti solid solution alloys with low Young's modulus were analyzed by using the cluster-plus-glue-atom model, in which an alloy structure is dissociated into a cluster part and a glue atom part, i.e. isolated clusters are linked with glue atoms. The cluster here is the nearest neighbor coordination polyhedron with a coordination number of 14 (CN14). It is confirmed that β-Ti solid solution alloys with low Young's moduli satisfy a universal cluster formula [CN14 cluster](glue atom)_x given by this model. Alloys, described by cluster formulas [MoTi₁₄]Ti, [MoTi₁₄]Nb, [MoTi₁₄]Nb₂ and [Mo(Ti₁₃Zr)]Nb₂, Ti-11.8Mo (mass fraction, %), Ti-11.2Mo-10.8Nb, Ti-10.1Mo-19.5Nb and Ti-9.2Zr-9.6Mo-18.7Nb were designed and the alloy rods with diameters of 3 and 6 mm were prepared by copper-mould suction-cast method, respectively. These suction-cast alloys possess monolithic bcc β-Ti structure. The introduction of low-modulus Nb as glue atoms weakens the cluster linking and decreases the Young's modulus. Further substitutions with low-modulus Zr reduces the Young's modulus to 72 GPa in the [Mo(Ti₁₃Zr)]Nb₂ alloy. Solution treatment plus subsequent water quenching decreases slightly the Young's moduli of the suction-cast alloys.