铝合金摩擦堆焊工艺与微观组织演变研究

    Research on Aluminum Alloy Friction Surfacing Process and Microstructure Evolution

    • 摘要: 采用摩擦堆焊技术在2024铝合金表面得到成型良好的6061铝合金堆焊层。适当提高轴向进给速度可以改善堆焊层的成型。堆焊层横截面呈流线组织,中心区域堆焊层与基板界面结合良好,但前进侧与后退侧界面处存在结合不足的缺陷。对堆焊层进行电子背散射衍射(EBSD)分析得出,摩擦堆焊过程中发生动态再结晶,堆焊层晶粒呈高度细化的等轴晶,且小角晶界比例提高。由于堆焊层不同区域热输入存在差异,晶粒细化程度和小角晶界比例略有不同。6061-T6铝合金经过摩擦堆焊,其热处理强化效果消失,堆焊层硬度相较于原始棒材发生一定程度的降低。

       

      Abstract: Well-formed 6061 aluminum alloy deposits were fabricated on 2024 aluminum alloy substrate by using friction surfacing, and the formation of the deposits can be improved by properly increasing the axial feed speed.The cross section structure of the deposit shows a streamlined structure.The interface between deposit and substrate in the central zone is well bonded, but there are some insufficient bonding defects at the advancing side and the retreating side.The electron backscattered diffraction (EBSD) analysis of the deposits shows that dynamic recrystallization occurs during the friction surfacing process, and the grains are highly refined and the proportion of low angle grain boundary increases.Due to different heat input in different zone of the deposit, the degree of grain refinement and the proportion of low angle grain boundary are slightly different.The heat treatment strengthening effect of 6061 aluminum alloy disappears during the friction surfacing process, therefore the hardness of the deposits is lower than that of the base metal.

       

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