Microstructure and mechanical properties of non-flammable Mg-8Al-0.3Zn-0.1Mn-0.3Ca-0.2Y alloy subjected to low-temperature, low-speed extrusion

Yohan Go, Su Mi Jo, Sung Hyuk Park, Ha Sik Kim, Bong Sun You, Young Min Kim

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

A new Mg alloy with the composition of Mg-8Al-0.3Zn-0.1Mn-0.3Ca-0.2Y was successfully fabricated by a low-temperature, low-speed indirect extrusion process. The extruded alloy showed excellent mechanical properties, i.e., a tensile yield strength of 379.3 MPa, ultimate tensile strength of 421.7 MPa, elongation of 11.3%, and yield asymmetry of 0.95, as well as a very high chip ignition temperature of 820 °C. The outstanding mechanical properties are attributed to the microstructural characteristics of the extruded alloy, that is, (i) grain boundary strengthening by fine recrystallized grains, (ii) precipitation hardening by abundant fine Mg17Al12 precipitates, and (iii) strain hardening by the deformed non-recrystallized region with a strong basal texture that is unfavorable for basal slip during tension. Electron backscatter diffraction results showed that no twinning occurred in the recrystallized grains, which had a very small size of approximately 800 nm, whereas {10–12} twins were formed in the non-recrystallized grains even at low compressive stress, which consequently increased the yield asymmetry.

Original languageEnglish
Pages (from-to)69-76
Number of pages8
JournalJournal of Alloys and Compounds
Volume739
DOIs
StatePublished - 30 Mar 2018

Keywords

  • Dynamic recrystallization
  • Extrusion
  • Magnesium alloys
  • Mechanical properties
  • Non-flammability
  • Yield asymmetry

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