Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
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Effect of Extrusion Conditions on Microstructures and Mechanical Properties of AM80 Magnesium Alloys

AM80 마그네슘 합금의 미세조직 및 기계적 특성에 대한 압출조건의 영향

  • Received : 2018.09.11
  • Accepted : 2018.11.23
  • Published : 2018.12.01
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Abstract

This study investigated the effect of extrusion conditions on microstructures and mechanical properties of AM80 magnesium alloys. The billets of magnesium alloy used for hot extrusion were prepared by permanent mold casting method, and its extrusion was hot direct extrusion with different extrusion conditions. The results of microstructural analysis showed that the main phases in the as-casted alloys were ${\alpha}-Mg$, ${\beta}-Mg_{17}Al_{12}$, and lamella $Mg_{17}Al_{12}$. Hot extrusion results, The tensile strength of the most soundly manufactured extruded bars (extrusion temp: $350^{\circ}C$, extrusion ratio: 27:1, ram speed: 2mm/s) was approximately 327MPa at room temperature. The increase in the mechanical properties of hot-extruded alloys was as a result of grain refinement by dynamical recrystallization during hot extrusion.

Keywords

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Fig. 1 Microstructures of as-casted AM80 Mg alloys; (a) ingot and (b) billet for hot-extrusion

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Fig. 2 Change in the Extrusion pressure of AM80 Mg Alloys during hot extrusion at different extrusion temperature and surface of as-extruded alloys

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Fig. 3 microstructures and average grain size of asextruded rods at different extrusion temperature; (a) 300℃, (b) 320℃, (c) 350℃ and (d) 380℃

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Fig. 4. Mechanical properties of the extruded rods withdifferent extrusion temperature.

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Fig. 5 Change in the extrusion pressure of AM80 Mg Alloy during hot extrusion at different extrusion ratio and surface of as-extruded alloys

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Fig. 6 Microstructures and average grain size of the extruded rods with different extrusion ratio; (a) 12:1, (b) 19:1 and (c) 27:1

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Fig. 7 Relationship between extrusion ratio and true strain.

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Fig. 8 Mechanical properties of the extruded rods with different extrusion ratio

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Fig. 9 Change in the extrusion pressure of AM80 Mg Alloys during hot extrusion with different ram speed and surface of as-extruded alloys

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Fig. 10 Microstructures and average grain size of the extruded rods alloy with different ram speed; (a) 2mm/s and (b) 4mm/s

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Fig. 11 Mechanical properties of the extruded bars with different extrusion ram speed

Table 1 Chemical composition of the AM80 Mg alloys. (wt%)

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