Homogeneity of microstructure and mechanical properties of ZK60 magnesium alloys fabricated by high strain rate triaxial-forging
Author(s): WU Yuanzhi, YAN Hongge, ZHU Suqin, CHEN Jihua, LIU Xianlan, LIU Anmin
Pages: 310-316
Year: 2014 Issue: 2
Journal: The Chinese Journal of Nonferrous Metals
Keyword: ZK60 magnesium alloy; triaxial-forging; microstructure; mechanical property;
Abstract: Triaxial-forging of ZK60 magnesium alloy was conducted on air hammer, and the microstructure evolution and the homogeneity of microstructures and properties were investigated. The result show that inhomogeneous deformation is detected in the forged specimen due to the friction between the hammer and specimen, and the actual deformation at the central part of the specimen is extensively larger than that at other part. A mixed structure of honeycomb-like coarse dynamic recrystallization (DRX) grains and island-like ultrafine DRX grains are obtained at the central part of the specimen at accumulated strain∑Δεof 3.3, while the structure at the edge part of the specimen consists of honeycomb-like coarse DRX grains and island-like twins. The ultimate tensile strength (UTS) decreases while the ductility increases from the edge part to centre part of the specimen at∑Δεof 3.3. Mechanical anisotropy is also detected in the forged specimen at ∑Δε of 3.3. However, the UTS and elongations at different directions range in 310.6-323.9 MPa and 21.9%-29.7%, respectively, which indicates that extensive anisotropy can be avoided by high strain rate triaxial forging technique. High strain rate triaxial forging is therefore identified as a potential technique for producing wrought magnesium with excellent mechanical properties.
Pages: 310-316
Year: 2014 Issue: 2
Journal: The Chinese Journal of Nonferrous Metals
Keyword: ZK60 magnesium alloy; triaxial-forging; microstructure; mechanical property;
Abstract: Triaxial-forging of ZK60 magnesium alloy was conducted on air hammer, and the microstructure evolution and the homogeneity of microstructures and properties were investigated. The result show that inhomogeneous deformation is detected in the forged specimen due to the friction between the hammer and specimen, and the actual deformation at the central part of the specimen is extensively larger than that at other part. A mixed structure of honeycomb-like coarse dynamic recrystallization (DRX) grains and island-like ultrafine DRX grains are obtained at the central part of the specimen at accumulated strain∑Δεof 3.3, while the structure at the edge part of the specimen consists of honeycomb-like coarse DRX grains and island-like twins. The ultimate tensile strength (UTS) decreases while the ductility increases from the edge part to centre part of the specimen at∑Δεof 3.3. Mechanical anisotropy is also detected in the forged specimen at ∑Δε of 3.3. However, the UTS and elongations at different directions range in 310.6-323.9 MPa and 21.9%-29.7%, respectively, which indicates that extensive anisotropy can be avoided by high strain rate triaxial forging technique. High strain rate triaxial forging is therefore identified as a potential technique for producing wrought magnesium with excellent mechanical properties.
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