钛中氦泡融合的分子动力学模拟

摘要

本文采用分子动力学方法模拟了金属钛中氦泡的融合，分析了氦泡融合对金属微结构的影响，对比了氦泡在金属块体内部与接近金属表面处融合的异同。研究表明：在金属块体内部，两氦泡的融合会在其周围诱发很多缺陷且范围逐渐扩大；直径均为1.77 nm的两氦泡的融合会在二者周围形成位错环，位错环内金属原子的排列与基底的一致；两氦泡发生融合后由哑铃状向椭球形演化。在接近金属表面处，由氦泡融合诱发的缺陷易于向金属表面移动，氦泡周围的金属易于向晶体结构恢复；两氦泡发生融合后由哑铃状向半球形演化。%Molecular dynamics simulations were performed to study the helium bubble coalescence in titanium . T he influence of helium bubble coalescence on the metal microstructure was analyzed .The bubble coalescences in the bulk metal and near the metal surface were compared . When helium bubbles lie in the bulk metal , a lot of defects are induced around by the bubbles coalescence and extend outward . The coalescence of helium bubbles with 1.77 nm diameter can form a dislocation loop around them . The helium bubbles after coalescence evolve from dumbbell shape toward ellipsoid shape .When helium bubbles lie near the metal surface ,the defects induced by bubbles coalescence are likely to move to the top surface ,and the metal around bubble tends to restore the crystal structure .The helium bubbles evolve from dumbbell shape tow ard hemispherical shape .