Cu_3Au中脱合金层产生内应力的分子动力学模拟

MOLECULAR DYNAMICS SIMULATION OF TENSILE STRESS INDUCED BY DEALLOYED LAYER IN Cu_3Au

Cu3Au在腐蚀或应力腐蚀时表层Cu原子择优溶解形成脱合金疏松层.对具有疏松层的三维晶体(约148 000个原子),用镶嵌原子方法(EAM)势进行了分子动力学模拟.结果表明,一旦出现疏松层就会产生一个拉应力,它使单端固定、单边存在疏松层的晶体发生弯曲,其挠度(或拉应力)随疏松层增厚以及空位浓度升高而升高.

During stress corrosion cracking of Cu3Au alloy, there is a dealloyed layer on the surface because of preferential dissolution of Cu, and there is a linear distribution of Cu vacancy concentration in the dealloyed layer. Molecular dynamics simulation has been done on the three-dimensional crystal (about 148,000 atoms) by employing the embedded-atom method (EAM) potential. Simulation shows that Cu3Au crystal in which there is a dealloyed layer on one surface and one end is fixed will be deflected after relaxing for a long time because of a tensile stress generated at or near the dealloyed layer interface. The deflection and then the tensile stress increases with increasing the depth of dealloyed layer and the vacancy concentration in the dealloyed layer.