Effect of Sc on Al_(3)Fe phase and mechanical properties of as-cast AA5052 aluminum alloy

The AA5052 aluminum alloy is widely used in automobile and aerospace manufacturing,and with the development of light-weight alloys,it is required that these materials exhibit better mechanical properties.Previous studies have demonstrated that the addition of Sc to aluminum alloys can improve both the microstructure and properties of the alloys.In this study,the effect of Sc on the Fe-rich phase and properties of the AA5052 aluminum alloy was studied by adding 0%,0.05%,0.2%,and 0.3%Sc.The results show that with the increase of Sc,the coarse needle-like Fe-rich phase gradually transforms into Chinese-script and then nearly spherical particles,reduce the size of Fe-rich phase,and refine the grain with increase of high angle grain boundaries(HAGBs).These microstructure changes enhance the strength of the AA5052 alloy through Sc addition.The ductility of the alloy is obviously improved because the addition of a lower amount of Sc changes the morphology of Fe-rich phase from needle-like into a Chinese-script,and it is subsequently reduced as a result of significant increase in HAGBs with increasing Sc content.

Effects of cold rolling and heat treatment on microstructure and mechanical properties of AA 5052 aluminum alloy

The microstructures and mechanical properties of homogenized-rolled AA5052 aluminum alloys with different rolling reductions and following annealing treatments were investigated by optical microscope, scanning electron microscope, X-ray diffractometer, micro-hardness and tensile tests. The results show that with increasing rolling reduction, the equiaxed grains are elongated along the rolling direction obviously, and accumulation of rolling reduction increases the work hardening effect, which results in the enhanced strength and degraded plasticity. When rolling reduction is 87%, the ultimate tensile strength reaches 325 MPa but elongation is only 2.5%. There are much more secondary phase precipitates after annealing treatment. With an increase of annealing temperature, the amount of precipitates increases and work hardening diminishes continuously. The elongation is improved to ~23% but the tensile strength is decreased to 212 MPa after annealing at 300 °C for 4 h, which are comparable to those of as-homogenized alloy.

DC AA 5052铝合金冷轧板沿厚度方向织构变化的X射线衍射分析

以不同变形量对预先经过热轧和再结晶退火的DC AA 5052直接冷却铸造铝合金板进行冷轧制后,采用X射线衍射和专用软件测试、计算并分析表层、1/4厚度层、中心层的织构极图和ODF图及有关数据,研究板厚度方向轧制织构的变化情况,以为改进轧制工艺、获得板厚度方向的织构织及性能均匀性提供依据。各变形量的试样之表层向1/4层、中心层方向,存在β织构逐渐增强的梯度;变形量逐渐增大到90%的过程中,沿板厚度方向β织构强度的变化梯度逐渐降低、体积分数逐步增大、强度逐渐增大并达到各层基本接近。

Formability of AA5052/polyethylene/AA5052 sandwich sheets

The formability of AA5052/polyethylene/AA5052 sandwich sheets was experimentally studied. Three kinds of AA5052/polyethylene/AA5052 sandwich specimens with different thicknesses of core materials were prepared by the hot pressing adhesive method. Then, the uniaxial tensile tests were conducted to investigate the mechanical properties of AA5052/polyethylene/ AA5052 sandwich sheets, and the stretching tests were carried out to investigate the influences of polymer core thickness on the limit dome height of the sandwich sheet. The forming limit curves for three kinds of sandwich sheets were obtained. The experimental results show that the forming limit of the AA5052/polyethylene/AA5052 sandwich sheet is higher than that of the monolithic AA5052 sheet, and it increases with increasing the thickness of polyethylene core.

无模无铆连接接头的塑性变形行为及工艺参数研究

为克服传统无铆连接工艺模具结构复杂、对中要求高等不足,提出了一种新型无模无铆连接工艺,并针对2 mm厚AA5052-H32铝合金板材开展了无模无铆接头塑性变形行为及工艺参数的研究。通过单轴拉伸实验和参数拟合获取了铝合金材料模型,并以此为材料数据建立了无模无铆接头成形过程有限元模型。此外,还分析了成形过程中板料的等效塑性应变、等效应力和材料流动情况,研究了冲头工艺参数对接头塑性变形行为的影响规律。实验与仿真结果表明,所建立的有限元模型具有较好的精度,[JP3]可以有效预测接头的成形过程,接头的颈部厚度、互锁值和凸起高度的预测误差均在10%以内,分别为9.4%、1.8%和0.1%;冲头直径、冲头圆角半径、冲头高度和冲头拔模斜度4种冲头工艺参数对接头的塑性变形行为和最终的接头形状有重要影响。

基于响应曲面法的5052铝板自冲铆接成形工艺参数优化

以汽车电池包上两层2 mm料厚的AA5052-H32铝板的自冲铆接作为研究对象,基于DEFORM-2D软件及响应曲面法对自冲铆接工艺参数进行优化。借助中心设计组合法及有限元模拟结果,建立工艺参数与底切量之间的数学关系式,通过分析可得,模具宽度与模具深度对底切量的交互式影响最大。以模具宽度、模具深度以及模具凸台高度作为设计变量,将底切量作为铆接成形质量的优化目标,利用Design Expert软件进行优化,得出铝板自冲铆接的优化工艺参数为:模具深度为1. 45 mm,模具宽度为8. 95 mm,模具凸台高度为-0. 15 mm,底切量的响应值为0. 609 mm。此外,借助铆接设备对优化方案进行试验验证,底切量的试验值为0. 546 mm,试验值与响应值之间的相对误差为10. 34%,验证了响应面法应用于铝板自冲铆接成形工艺参数优化的准确性与可靠性。