Zhenyan Zhang

Effects of Cu and Mn on mechanical properties and damping capacity of Mg-Cu-Mn alloy

The effects of Cu and Mn additions on mechanical properties and damping capacity of Mg-Cu-Mn alloy were investigated. The tensile properties and damping capacity at room temperature of as-cast Mg-Cu-Mn alloy were tested. The microstructure was studied using optical microscope, X-ray diffraction and scanning electron microscope. The Hall-Petch relation and Granato-Lucke model were used to explain the influences of Cu and Mn additions on the tensile properties and damping capacity of Mg-Cu-Mn alloy. The results show that Cu and Mn additions remarkably reduce the grain size of Mg-Cu-Mn alloy, but have little influence on phase composition and solute atoms concentration, the tensile properties increase obviously and the internal friction of Mg-Cu-Mn alloy decreases with grain refining.

Effects of annealing process on sagging resistance of cold-rolled three-layer Al alloy clad sheets

Abstract Homogenization annealing of the 7050/6009 bimetal slab prepared by direct-chill casting was investigated and its effects on microstructural evolution, composition distribution and mechanical properties in the interfacial region of the bimetal were studied. The results show that the optimized homogenization annealing process was 460 °C for 24 h. After homogenization annealing, the Zn-rich phases and Al 15 (FeMn) 3 Si 2 phases were precipitated at the interface of the bimetal. The diffusion layer thickness of homogenized bimetal increased by 30 µm from 440 to 480 °C for 24 h, while it increased by 280 µm from 12 to 36 h at 460 °C. The Vickers hardnesses at 6009 alloy side and interface of the bimetal decreased after homogenized annealing and grain coarsening was considered as the dominating softening mechanism. The hardness variation at 7050 alloy side was complicated due to the combined action of solution strengthening, dispersion strengthening and dissolution of reinforced phases.