Mg对三元Al-Cu-Mg合金位错分布组态的影响

Effects of Mg on the Distribution of Dislocations in AI-Cu-Mg Alloy

摘要:

对经均匀化退火，不同变形锻造，固溶处理的样品，借助TEM，研究了Mg对三元Al-Cu-Mg合金位错分布组态的影响。研究结果表明：Cu原子与Al原子在变形与时效过程中形成了Al2Cu沉淀相而降低了Cu元素在Al基体中的浓度，减少了Cu、Mg元素的交互作用。由于Mg元素有较大的原子半径，与基体产生了很大的晶格畸变能和内摩擦力，因此Mg元素在Al基体中对位错的分布式滑移（交滑移）起着明显的阻滞作用，限制了胞状组织的形成。与典型的高能层错金属与合金中位错呈胞状组织不同，Al-Cu-Mg合金中的位错呈准均匀的Taylor晶格分布，这种分布可以降低合金的自由能。

Abstract:

The effects of Mg element on the distribution of dislocations in Al-Cu-Mg alloy have been investigated. It has been shown that the interaction between Mg and Cu atoms was decreased since the concentration of Cu in Al matrix decreases due to the formation of Al2Cu precipitates during deformation and aging. The Mg element blocks the distributed glide of dislocations and thus inhibits the formation of cell structures due to the large atom radius, producing high aberrance energy and internal friction in Al matrix. Compared with the cell structures in typical metals and alloys with high stacking-fault energy, the dislocations in Al-Cu-Mg alloy are quasi-uniformly distributed and can decrease the free energy, named as the Taylor lattice distribution.