Mechanical properties and failure characteristics of cast and extruded Mg97Y2Zn1 alloys with LPSO phase

Mitsuhiro Okayasu, Shuhei Takeuchi, Masafumi Matsushita, Naoya Tada, Michiaki Yamasaki, Yoshihito Kawamura

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Mechanical properties and failure characteristics of Mg97Y2Zn1 (at%) alloys, prepared by gravity casting and extrusion processes, are examined experimentally. High tensile and fatigue strengths are obtained for extruded Mg97Y2Zn1 alloys, with the values being approximately twice as high as those for cast Mg97Y2Zn1 alloys. Such high strengths are attributed to the high internal stress arising from the complicated microstructure and severe lattice strain in the α-Mg and long-period stacking order phases. On the other hand, a high fracture strain is obtained for cast Mg97Y2Zn1 alloy, which is affected not only by the lower internal stress, but also severe kink deformation. The failure characteristics, e.g., crack growth characteristics are examined via direct observation during tensile and fatigue tests at micro- and nano-scales. Meandering fatigue crack growth is obtained for the cast Mg97Y2Zn1 alloys. The mean roughness of the fracture surface for cast Mg97Y2Zn1 alloys is more than twice as high as that for commercially available AM60 and AZ91 cast alloys. A coarse fracture surface that was observed in the cast Mg97Y2Zn1 alloys would make severe roughness-induced crack closure, leading to high fatigue strength.

Original languageEnglish
Pages (from-to)14-29
Number of pages16
JournalMaterials Science and Engineering A
Volume652
DOIs
Publication statusPublished - Jan 15 2016

Keywords

  • Crack growth characteristic
  • Failure analysis
  • Long-period stacking order phase
  • Magnesium alloy
  • Mechanical property

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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