Al-Cu-Mg合金中位错与S相的相互作用

Interaction between dislocations and S-phase precipitates in Al-Cu-Mg alloy

为了研究含第二相的铝合金塑性变形的微观机制,用透射电子显微术研究了过时效Al-Cu-Mg合金在静载拉伸过程的塑性变形时位错与S相(Al2CuMg)沉淀物的相互作用。研究结果表明,在外加应力作用下,首先沉淀物与α-相基体间的相界释放出位错,同时,α-Al母体中的运动位错向着沉淀物运动,随后,这些运动位错在沉淀物前与沉淀物相界释放出的位错相互作用形成位错缠结,故此塑性变形过程可称为位错缠结机制。该研究结果说明,Al-Cu-Mg合金中S相的存在,对位错的运动和塑性变形有很大的阻碍作用,因而能明显增加材料的流变应力和加工硬化能力。

To study the plastic deformation micromechanism in aluminium alloy containing second phase, the plastic deformation of over-aged AI-Cu-Mg alloy under tensile loading is investigated by transmission electron microscopy. The interaction mechanism of dislocations with S-phase （Al2CuMg） precipitates is examined. The investigation indicates that under tensile loading the emission of dislocations from phase boundary between the precipitates and α-Al firstly occurs and meanwhile the moving dislocations in α-Al matrix move towards the precipitates, and then the moving dislocations are obstructed at the precipitates and dislocation tangle forms due to the interaction between the moving dislocations and the dislocations emitted from phase boundaries of precipitates. The plastic deformation process is called the dislocation tangle mechanism. The investigative result demonstrates that the S-phase in Al-Cu-Mg alloy has a big obstruction effect for dislocation movement, and so the S-phase can obviously increase flow stress and cold work-hardening ability.