Y对6082铝合金铸轧板微观结构及性能的影响

Effects of Y on the Microstructure and Properties of 6082 Aluminum Alloy Cast-Rolled Plates

本工作研究了添加微量Y元素对双辊铸轧6082铝合金微观组织及力学性能的影响。设计不同含Y量,使用双辊铸轧机制备6082铸轧板材,采用X射线衍射、金相显微观察、扫描电子显微分析等手段,研究了合金中Y对6082铝合金铸轧板组织及性能的影响。结果表明:Y元素有明显的细化效果,Y含量为0.35%(质量分数,下同)时,板材边部和心部平均晶粒尺寸达到最小,分别为30.9μm和25.7μm,且此时板材性能最好,抗拉强度、屈服强度和延伸率分别为200.5 MPa、129.9 MPa和14.9%。继续添加Y,组织中的杂质相和稀土化合物显著增加,材料的塑形大幅降低。经分析,Y元素偏聚于晶界,形成的Al_(3)Y、Y_(5)Si_(3)等化合物不仅可抑制晶界的迁移,起到一定的细化作用,还能改善晶界上粗大的共晶相,Y与合金中的Fe元素发生交互作用,使组织中脆性针状富铁相向颗粒状转变,改善合金的塑性。

This study investigated the influence of adding trace amounts of Y element on the microstructure and mechanical properties of 6082 aluminum alloy produced by dual-roll casting.Different Y contents were designed,and 6082 cast-rolled plates were prepared using a dual-roll casting machine.X-ray diffraction,metallographic observation,and scanning electron microscopy were employed to study the effect of Y on the microstructure and properties of the cast-rolled plates.The results show that Y element has a significant refining effect.The average grain sizes of the edge and center regions of the plate with a Y content of 0.35wt%reach a minimum at 30.9μm and 25.7μm,respectively.The mechanical properties of the plate are the best at this Y content,with tensile strength,yield strength,and elongation of 200.5 MPa,129.9 MPa,and 14.9%,respectively.With further addition of Y,the impurity phases and rare earth compounds in the microstructure increase significantly,and the formability of the material decreases substantially.Analysis reveals that Y element segregates at grain boundaries,forming compounds such as Al_(3)Y and Y_(5)Si_(3),which can inhibit grain boundary migration and contribute to grain refinement.Additionally,Y interacts with Fe elements in the alloy,transforming the coarse eutectic phases on the grain boundaries into finer particles and improving the alloy’s ductility.