AZ80镁合金轮毂强力旋压工艺及组织性能研究

Microstructure and Mechanical Properties of Magnesium Alloy AZ80 Wheel Fabricated by Power Spinning

采用强力旋压技术对AZ80镁合金轮毂坯料进行了减薄,研究了旋压温度、旋轮进给比和壁厚减薄率对AZ80镁合金轮毂的旋压成形性、微观组织和机械性能的影响。结果发现：当旋压温度为420℃,进给比为0.1 mm·r^-1时,旋压轮毂可获得较优的旋压成形性和均匀的微观组织;旋压温度从300℃升高到420℃时,由于发生动态再结晶的组织增多,晶粒尺寸增大且组织更为均匀;进给比对旋压工件显微组织的影响并不显著,随着旋压时进给比增大,晶粒尺寸有轻微程度地降低;减薄率的提高会使晶粒尺寸明显下降且平均硬度值上升。此外,电子背散射衍射（EBSD）结果显示,轮毂坯料经过加热旋压后大部分晶粒的c轴与径向近似平行,但部分晶粒的取向朝轴向发生了轻微偏转。当旋压采用50%的减薄率时,可获得较好的力学性能：屈服强度（YS）、抗拉强度（UTS）和延伸率分别为169,312 MPa和14.1%,相对于铸态组织分别提高了181%,160%和182%。

The power spinning of AZ80 alloy wheels was conducted innovatively. The effects of processing parameters including spinning temperature, feed ratio and thickness reduction on the deformation ability, mierostructures and mechanical properties were investigated. The results showed that a good spinning ability and microstructure could be obtained when the spinning was carried out at a temperature of 420 ℃ and a feed ratio of 0.1 mm·r^-1. With the deforming temperature increasing from 300 to 420 ℃ , the grain size increased and a more uniform microstructure was obtained induced by a larger extent of dynamic recrystallization. The variation of feed ratio had a slight influence on the microstructure. A larger feed ratio led to a finer microstructure. The grain size decreased and the mi- crohardness increased significantly with increasing thickness reduction. Moreover, the electron backseatter diffraction （EBSD） results showed that the c-axes of most grains were approximately parallel to the radial direction, and some of them had a slight deflection to- wards the axial direction. Furthermore, a yield strength （YS） of 169 MPa, an ultimate tensile strength （UTS） of 312 MPa and an elongation of 14.1% were obtained when a thickness reduction of 50% was adopted. Compared to the as-cast blank, the YS, UTS and elongation increased by 181% , 160% and 182% , respectively.