The formation of deformation bands in f.c.c. crystals

Dynamic grain evolution of a magnesium alloy AZ31 was studied in compression at 673 K (0:73T m ) by optical and SEM/OIM microscopy. The flow curve shows rapid hardening accompanied by a stress peak at a relatively low strain (" p ¼ 0:12), followed by strain softening and then a steady state flow stress at high strains. Fine grains evolved at corrugated grain boundaries at around " p and developed rapidly during strain softening, finally leading to a full structure of equiaxed fine grains. Such characteristics of new grain evolution and flow behavior are apparently similar to those in conventional, i.e. discontinuous, dynamic recrystallization (DRX). On the other hand, kink bands were observed frequently near corrugated grain boundaries and also in grain interiors, even around " p . The misorientation of the boundaries of the kink bands increases rapidly during strain softening and approaches a saturation value of around 43 at high strains. The average size of the regions fragmented by kink bands is almost the same as that of the new grains. It is concluded, therefore, that new grain evolution in this alloy is controlled by a deformation-induced continuous reaction, i.e. continuous DRX.

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“…Such bands have been called kink bands in Mg alloys. 10,11) Their presence is confirmed in Figs. 3 and 4.…”

supporting

confidence: 60%

Dynamic Evolution of New Grains in Magnesium Alloy AZ31 during Hot Deformation

2003

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“…4(b)). It was observed from the surface morphology that several deformation bands based on kink bands (Higashida et al, 1986) are frequently evolved and traversed or intersected in some grain interiors. The boundaries of these bands can be seen in the OIM map in Fig.…”

Section: Mechanical and Microstructural Behaviors During Hot Compressionmentioning

confidence: 99%

Mechanical Properties of Fine-Grained Magnesium Alloys Processed by Severe Plastic Forging

Sakai¹,

Miura²

2011

Magnesium Alloys - Design, Processing and Properties

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“…5, the flow stress curves in forging showed a tendency towards work hardening, although apparent softening by temperature rise during forging was observed in a few forged specimens. Formation of a kink-deformation band in the LPSO phase and -Mg phase region may strengthen the Mg alloys, 13) because macro kink deformation bands that were formed perpendicular to the primary slip direction 19) became an obstruction to basal slipping.…”

Section: Microstructurementioning

confidence: 99%

Forgeability and Flow Stress of Mg-Zn-Y Alloys with Long Period Stacking Ordered Structure at Elevated Temperatures

et al. 2009

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To develop a forging process for high strength Mg-Zn-Y alloys with a long period stacking ordered (LPSO) structure, the forgeability and flow stress of Mg 97 Zn 1 Y 2 (at%) alloys were investigated with the upsettability test at an initial strain rate of 0.55 s À1 . As-cast and extruded Mg 97 Zn 1 Y 2 alloys can be successfully forged without fracture up to 0.5 and 1.0 respectively of average equivalent strain at a forging temperature of 773 K. To remove the influence of the temperature change during upsetting from the experimentally obtained flow stress curve, the isothermal flow stress curve was estimated by combining experimental results with finite element analysis. Furthermore, the mechanical properties of the forged Mg-Zn-Y alloys were measured, and the influence of microstructure on the forging properties was discussed.

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The formation of deformation bands in f.c.c. crystals

Cited by 101 publications

References 21 publications

Dynamic Evolution of New Grains in Magnesium Alloy AZ31 during Hot Deformation

Dynamic Evolution of New Grains in Magnesium Alloy AZ31 during Hot Deformation

Mechanical Properties of Fine-Grained Magnesium Alloys Processed by Severe Plastic Forging

Forgeability and Flow Stress of Mg-Zn-Y Alloys with Long Period Stacking Ordered Structure at Elevated Temperatures

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