5052铝合金渐进成形件变形区微观分析与研究

Microscopic analysis and study on deformed field of 5052 aluminium alloy workpieces produced by incremental forming

为认识5052铝合金在渐进成形过程中的塑性变形特点,使用热场发射扫描电镜,结合电子背散射衍射技术(EBSD)对制件变形区的微观组织、微区晶粒取向和微区织构演变进行了研究。结果表明:在"一拉两压"三向应力作用下,晶粒沿壁向受拉,径向、切向受压。成形角较小时,径向压力较大,晶粒破碎现象明显,随着成形角变大,碎晶现象有所减弱。成形角增大,坯料塑性变形增加,变形区中小角度晶界的比例明显增加,大角度晶界的分布趋于均匀。渐进成形试样变形区的织构含量较低,有利于提高坯料的塑性成形能力。

To understand the deformation characteristic of 5052 aluminium alloy in incremental forming,a heat field emission electron microscopy with electron backscattered diffraction(EBSD)technology was used to study the micro structure,micro grain orientation,and micro texture evolution in the deformed field.The results show that grains were stretched along the wall direction of workpieces and compressed along radial and tangential directions under tri-axial stresses(one for tensile and others for compressive).With the larger radial force,the situation of grain broken is obvious with small forming angle,but it becomes less severe with a larger forming angle.A larger forming angle increases the plastic deformation,which increases the proportion of small angle grain boundaries and makes the distribution of big angle grain boundaries tend to be uniform.Finally,in the incremental formed workpieces,the proportion of micro textures is much smaller,which is beneficial to enhancing the plastic forming capacity of workpieces.