Study of the microstructures and mechanical properties of ZK61 magnesium alloy cylindrical parts with inner ribs formed by hot power spinning

Abstract

Cylindrical parts with inner ribs (CPIR) of magnesium alloy have increasingly become a research focus to adapt the continuous improvement of lightweight requirement. The hot power spinning (HPS) method was proposed to form the magnesium alloy CPIR, and the microstructures, textures, and mechanical properties of blank and spun workpiece at cylindrical wall (CW) and inner rib (IR) were analyzed experimentally. The results show that the average grain size at CW and IR of spun workpiece is refined from 2.49 μm of blank to 1.88 μm and 2.11 μm, respectively. The c-axis of most grains at CW and IR of spun workpiece is deflected from tangential direction (TD) to radial direction (RD) by 90° and 72°, respectively. Compared with blank, the elongation at CW and IR of spun workpiece is increased by 52.2% and 39.8%, respectively. The yield strength and ultimate tensile strength of IR are basically the same as those of blank, while those of CW are decreased by 6.5% and 3.9%, respectively. The difference of macro fracture directions of tensile specimen of blank and spun workpiece is resulted from the change of grains c-axis direction and the increase of grain freedom degree around c-axis.