材料期刊网

采用计算机模拟技术创建钛α相和β相晶粒、α相中 刃位错及位错塞积形成的微裂纹原子集团模型。利用递归法（Recursion）计算了位错、裂纹及α相晶粒的电子结构（费米能级、结构能、环境敏感镶嵌能等），计算并分析了合金元素Mo、V对β相原子结合能的影响。结果表明：氢在位错处的环境敏感镶嵌能较低，易于在位错处聚积，形成氢原子气团。位错对氢原子气团的“钉扎”作用使钛合金局部硬化，使位错运动受阻塞积形成微裂纹。裂纹尖端费米能级高于裂纹其他区域，电子从裂纹尖端流向裂纹其他区域造成电位差，在电解质作用下裂纹尖端阳极分解腐蚀。拉应力与裂纹处的氢气压使裂纹解理或沿晶延伸，促进应力腐蚀的发展。合金元素Mo、V有利于α钛合金中β相的形成，阻止裂纹在α相中扩展，提高合金应力腐蚀抗力。

The atomic cluster models of αandβTi grains, edge dislocation in αgrains and the crack formed with edge dislocation accumulation were set up by computer simulation technique. The electronic structure (Fermi energy level, structure energy, environment sensitive embedding energies etc) of αTi grains, edge dislocation and the crack were calculated by using Recursion method. The effect of alloys element Mo and V on βphase atomic binding energy was calculated and analyzed. The results show that: H prone to gather on the edge dislocation and form H atomic group as the environment sensitive embedding energies is smaller when H is at the edge dislocation. It makes Ti alloys local harden and edge dislocation blocking and forming crack that the edge dislocation fix the H atomic group. As the Fermi energy of the crack tip is higher than that of other area, so the electron run to other area of the crack from the crack tip, which make the electric potential difference between the crack tip and the other area of the crack. The crack tip decomposes as anode under the electrolyte. The tensile force and H air pressure at the crack make the crack cleavage or stretch along grains boundaries, which facilitates the stress corrosion. The alloys element Mo and V can enhance Ti alloys stress corrosion resistance by catalyzingβphase which stops the crack expand in αTi.