Effect of Long-Period Stacking Order Phase and α-Mg Phase on Strength and Ductility of Mg-Zn-Y Alloy

Masafumi Noda; Yoshihito Kawamura

doi:10.4028/www.scientific.net/MSF.706-709.1237

Paper Titles

A Differential Scanning Calorimetric Study of the Mg-Cu-Y System
p.1215

C Fibres - Mg Matrix Composites Produced by Squeeze Casting and Friction Stir Processing: Microstructure & Mechanical Behaviour
p.1221

Improvement in Mechanical Properties of Coarse-Grained AZ61 Mg Alloy by Multidirectional Forging and Ultrafine Grain Refinement
p.1227

Effect of Grain Size on Fatigue Crack Propagation in Extruded AZ31 Magnesium Alloys
p.1233

Effect of Long-Period Stacking Order Phase and α-Mg Phase on Strength and Ductility of Mg-Zn-Y Alloy
p.1237

Microstructure of the High-Strength Magnesium Alloy on Cylinder Upsetting
p.1243

Creep Behavior and Microstructures in Grain Boundary Strengthened Mg-Al-Ca Thixomolded^® Alloys
p.1249

Evolution of Texture and Microstructure of AZ31 Mg Alloy Sheet at High Strain Rates
p.1255

Microstructure and Mechanical Properties of Magnesium Alloy Prepared by Repetitive Upsetting
p.1261

HomeMaterials Science ForumMaterials Science Forum Vols. 706-709Effect of Long-Period Stacking Order Phase and...

Effect of Long-Period Stacking Order Phase and α-Mg Phase on Strength and Ductility of Mg-Zn-Y Alloy

Abstract:

Mg alloys are lightweight structural alloys that normally have a good castability and machinability as well as an excellent specific strength and rigidity. However, the mechanical properties of Mg alloys are inferior to those of Al alloys, and their range of industrial applications is limited. Recently, Mg–Zn–Y alloy has been found to show a high tensile yield strength with a good elongation. The alloy has a long-period stacking order (LPSO) phase as the secondary phase in an α-Mg phase. In general, the tensile yield strengths of LPSO-type Mg alloy are known to be markedly enhanced by the formation of kink bands in the LPSO phase and by microstructural refinement of the α-Mg phase during plastic deformation. The separate roles of the LPSO phase and the α-Mg phase in relation to the mechanical properties of high-strength LPSO-type Mg alloy were investigated at ambient and high temperatures. For high strengths at ambient and high temperatures, it was important that the α-Mg phase consisted of a fine-grain region and a nonrecrystallized region, and that the LPSO phase remained as a block-type phase. On the other hands, it was necessary to change the LPSO phase from a block-type phase into a plate-type phase by heat treatment before tensile testing to improve the ductility of the alloy while maintaining its tensile yield strength. Microstructural control of the LPSO phase and the α-Mg phase is necessary to obtained Mg–Zn–Y alloy with superior mechanical properties at ambient-to-high temperatures.