Microstructure Evolution of Mg-4.5Zn-0.75Er Alloy Containing I-Phase during Hot Compression
| Autor: | Yuan Sheng Yang, Ji Xue Zhou, Ke Liu, Cui Cui Sun, Wen Bo Du |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science Scanning electron microscope Mechanical Engineering Metallurgy Alloy 02 engineering and technology Flow stress engineering.material 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure 01 natural sciences law.invention Deformation mechanism Optical microscope Mechanics of Materials law 0103 physical sciences Hardening (metallurgy) Dynamic recrystallization engineering General Materials Science 0210 nano-technology |
| Zdroj: | Materials Science Forum. 898:144-152 |
| ISSN: | 1662-9752 |
| DOI: | 10.4028/www.scientific.net/msf.898.144 |
| Popis: | The microstructure evolution of the Mg-4.5Zn-0.75Er alloy containing quasicrystalline phase (I-phase) during heat treatment and hot compression was investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that the as-cast alloys mainly consisted of α-Mg matrix and I-phase. The I-phase with different morphologies could be found at both matrix and interdentritic boundaries. The I-phase almost dissolved into the matrix at 460 °C, meanwhile, some magnesium-rare earth phase (Mg-Er phase) was precipitated and the volume fraction increased with prolonging the solid solution time. The true stress-strain curve obtained from the hot compression test showed the flow stress first increased to a maximum and then decreased to a steady state. It indicated that the dynamic competition took place between the working hardening and working softening during hot compression. Moreover, the main deformation mechanism was twining at strain of 0.08 for the as-solution alloy; with the increase of the strain, dynamic recrystallization (DRX) grains appeared at original grains and twins boundaries. Lots of nanoscale I-phase which pined and hindered dislocation precipitated within the matrix during hot compression process. |
| Databáze: | OpenAIRE |
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