PT Journal
AU Li, T
   Bu, D
   Yuan, J
   Han, X
   Du, Z
   Sun, Z
   Peng, Y
   Zhang, K
TI Microstructure, Mechanical Properties and Strengthening Mechanism of Back Extruded WE71 Magnesium Alloy Cylindrical Part
SO Manufacturing Technology Journal
PY 2023
BP 475
EP 484
VL 23
IS 4
DI 10.21062/mft.2023.049
DE Magnesium Alloy; Back Extrusion; Strengthening Mechanism; Grain Refinement
AB In the present work, the microstructure, crystal orientation, mechanical properties and strengthening mechanisms for different regions of WE71 cylindrical parts have been investigated. The results showed that from inner wall to outer wall, second phases density, DRX fraction decreased but average grain size increased, which is well agree with the strain state and metal flow during back extrusion. For compression area, α//ED texture type can be found in region a, but α directions deflects from ED to TD at a certain angle for region b and c. For shear area, α directions deflects from ED to TD about 10°~45°. For stable forming area, the texture is close toα//ND. After peak ageing, a large number of nanometer scaled β' phases were formed and uniformly distributed in the Mg matrix, while zigzag GP zone and RE-hexagons precipitates can also be found in the peak-aged alloy. Tensile properties for region c in compression area are the lowest: UTS, YS and EL are 322 MPa, 215 MPa and 2.5%, respectively. Furthermore, for the stable forming area, the UTS, YS and EL of 283 MPa, 187 MPa and 19% in the region f are the highest, but the strength of region g is the lowest, which is related to the grain size and volume fraction of second phases on flow lines. The strengthening contributes from fine-grain strengthening, texture strengthening and Orowan strengthening.
ER