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本文研究了完全时效状态的 AI-Mg-Si 合金在低塑性应变下的变形行为。无锰合金(BD_3)的塑性变形形成了狭窄的滑移带,它们的间距随着应变的增加稍微变窄。该合金在低应变下发生晶间破断,因为,滑移带端部的高应力集中,使空洞集结在晶界沉淀物上,然后,空洞在 PFZ 内聚结而扩大。两种含锰合金(BD_6和 BD_8)都含有直径为0.1微米、体积分数分别为0.4%和1.1%的非共格α-Al_(12)Mn_3Si 强化相,在低应变下,这两个合金都出现了间距较BD_3稍窄的滑移带,但是,在 BD_8合金中,随着应变的增加,滑移带间距交窄直到9%应变为止,之后不再变化。Mn 相明显地降低了滑移事端部的应力集中,从而使得滑移带横向变宽,并且其大小随着合金晶粒的细化而进一步地减小。曾用半定量分析方法研究了这两个因素对局部晶界应力的影响。其结论是:在低应变时,因为所产生的应力。集中不足以使晶界沉淀物破裂,所以 BD_6和 BD_8合金的晶间破坏受到了抑制。
In this paper, the deformation behavior of AI-Mg-Si alloys under full plastic deformation under full plastic deformation was studied. The plastic deformation of the manganese-free alloy (BD_3) forms a narrow slip band, with their pitches slightly narrowing as the strain increases. The alloys undergo intergranular fracture at low strain because the high stress concentration at the ends of the slip band causes voids to build up on the grain boundary precipitates and the voids then coalesce and expand in the PFZ. Both manganese-containing alloys (BD_6 and BD_8) contain a non-coherent α-Al_ (12) Mn_3Si reinforcing phase with a diameter of 0.1 μm and a volume fraction of 0.4% and 1.1%, respectively. At low strain, However, in BD_8 alloy, as the strain increases, the slip band spacing narrows until 9% strain, and then it does not change any more. The Mn phase significantly reduces the stress concentration at the end of the slip event, causing the slip band to laterally widen and its size to decrease further as the alloy grains refine. Semi-quantitative analysis methods have been used to study the influence of these two factors on the local grain boundary stress. The conclusion is: at low strain, due to the stress that is generated. Due to insufficient concentration of grain boundary precipitates, the intergranular damage of BD_6 and BD_8 alloys was suppressed.