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

Hiromi Miura; M. Ito

doi:10.4028/www.scientific.net/MSF.706-709.1227

Paper Titles

HRTEM Observation of Precipitates in Mg-Gd-Zr and Mg-Y-Zr Alloys Aged at 423 K
p.1205

Improving Corrosion Resistance of MRI 230D Mg Alloy by Hybrid Coating of Laser Surface Alloying and Plasma Electrolytic Oxidation
p.1209

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

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

Abstract:

A commercial AZ61 magnesium (Mg) alloy composed of coarse initial grains was multi-directionally forged (MDFed) under decreasing temperature conditions from 673 K to 463 K up to a cumulative strain of ΣΔε = 6.4 at a true strain rate of 3 × 10^-3 s^-1. A pass strain of Δε = 0.8 was employed. The average grain size decreased gradually with an increase in the cumulative strain. After straining to ΣΔε = 6.4 (i.e., after 8 passes of MDF), equiaxed ultrafine grains (UFGs) with an average size of approximately 0.8 μm were uniformly produced. These grains were relatively coarse as compared with MDFed Mg alloys having initially finer grains. The hardness of the AZ61 Mg alloy increased monotonically up to 910 MPa with decreasing grain size. The Hall-Petch relationship held within this experimental condition.