Microstructure Of Magnesium Alloy Sheets Research Articles

Microstructure of AZ31 Magnesium Alloy deformed by indentation-flattening compound deformation technology

Characteristic of indentation-flattening compound deformation technology (IFCDT) is discussed, and the parameters of IFCDT are defined. Performance of magnesium alloy AZ31 sheet deformed by IFCDT is researched. The effect of IFCDT coefficient, temperature and reduction ratio on the microstructure of magnesium alloy sheet is analyzed. The research results show that the volume fraction of the twin crystal decreases gradually and the average grain size increases with increasing of coefficient of IFCDT. With increase of the reduction ratio, the volume fraction of the twin crystal gradually increases, and the average grain size also increases. With increase of deformation temperature, the volume fraction of the twin crystal decreases gradually, and the twin crystal grain size increases.

Controlling the microstructure of magnesium alloy sheet during rolling

A hot rolled magnesium alloy sheet embedded in a steel block was rolled together with 3% thickness reduction at room temperature, 373K, and 673K. Tensile twins were observed after the rolling, which could not be found when the magnesium alloy sheet was rolled without the steel block. The twin fraction was the highest at 373K because of thermal expansion and activating non-basal slip systems at high temperature. Electron back-scattered diffraction analysis and finite element simulations confirmed that the steel block with higher strength played an important role in generating compressive stress along the transverse direction in the magnesium alloy sheet. The compressive stress could increase owing to suppression of thermal expansion in the magnesium alloy sheet at 373K. The yield stress and the tensile stress became higher in the rolled specimen with the steel block at 373K than in the specimen without it owing to grain refinement caused by tensile twins.

Effects of Annealing Treatment on the Microstructure and Mechanical Properties of Magnesium Alloy Sheets

The microstructure of magnesium alloy sheets (nominal composition Mg–6Zn–Y in at. %) was investigated with the Optical Microscope (OM), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) technique after the annealing treatment. Tensile test at room temperature was performed to show the influence of annealing treatment on mechanical properties. Experimental results indicate that there are a large number of twin crystals appearing in microstructure of the extruded Mg-Zn-Y alloy sheet at 350 °C. The distinct icosahedral phase appears on the α-Mg matrix in granular form and the strength gets largely improved to the maximum. The uniform distribution of isometric crystal contributes to the best elongation at the annealing temperature of 400 °C.