Microstructure and Mechanical Properties of Extruded Mg-Zn-Y Alloys with 14H Long Period Ordered Structure

The compositional dependence of mechanical properties and microstructural change of the extruded Mg-Zn-Y alloys has been investigated in the effort to develop a high strength Mg-Zn-Y alloy with long period ordered (LPO) structure. The extruded alloy Mg96Zn2Y2 exhibited a high yield strength of 390 MPa and elongation of 5% at room temperature, and of more than 300 MPa even at the elevated temperature of 473 K. The heat-treated ingot metallurgy (I/M) Mg-Zn-Y alloys containing very small amounts of yttrium and zinc are characterized by a lamellar phase constructed of 2H-Mg and 14H-LPO structures. Extrusion of the Mg-Zn-Y I/M alloys with LPO structure led to refinement of � -Mg grains and high dispersion of a hard lamellar phase consisting of torn-off 2H-Mg and bent LPO structures with random grain boundaries, resulting in strengthening of the alloys.

[1]  T. Itoi,et al.  Long period stacking structures observed in Mg97Zn1Y2 alloy , 2004 .

[2]  Y. Kawamura,et al.  Formation process of unique microstructure in rapidly solidified Mg97Zn1Y2 alloy , 2004 .

[3]  M. Nakamura,et al.  Quasicrystal strengthened Mg-Zn-Y alloys by extrusion , 2003 .

[4]  Zhang Shaoqing,et al.  Microstructures of MgZnZrRE alloys with high RE and low ZN contents , 1994 .

[5]  A. Luo.  Recent Magnesium Alloy Development for Automotive Powertrain Applications , 2003 .

[6]  T. Mukai,et al.  Ductility enhancement in AZ31 magnesium alloy by controlling its grain structure , 2001 .

[7]  A. Inoue,et al.  Long-period ordered structure in a high-strength nanocrystalline Mg-1 at% Zn-2 at% Y alloy studied by atomic-resolution Z-contrast STEM , 2002 .

[8]  Y. Kawamura,et al.  Corrosion Behavior of Rapidly Solidified Mg-Zn-Y Alloy Ribbons , 2003 .

[9]  Y. Kawamura,et al.  Structure and Mechanical Properties of Rapidly Solidified Mg97Zn1RE2 Alloys , 2003 .

[10]  Zhiping Luo,et al.  High-resolution electron microscopy on the X-Mg12ZnY phase in a high strength Mg-Zn-Zr-Y magnesium alloy , 2000 .

[11]  D. Bae,et al.  High Strength Mg-Zn-Y Alloy Containing Quasicrystalline Particles. , 2001 .

[12]  A. Inoue,et al.  Local chemistry of a nanocrystalline high-strength Mg 97 Y 2 Zn 1 alloy , 2002 .

[13]  Zhiping Luo,et al.  Strengthening effects of rare earths on wrought MgZnZrRE alloys , 1995 .

[14]  D. Bae,et al.  Deformation behavior of Mg–Zn–Y alloys reinforced by icosahedral quasicrystalline particles , 2002 .

[15]  Y. Kawamura,et al.  Mechanical properties of warm-extruded Mg¿Zn¿Gd alloy with coherent 14H long periodic stacking ordered structure precipitate , 2005 .