Hot and Cold Forming Behaviour of Magnesium Alloys AZ31 and AZ61

Chabbi, Lotfi; Lehnert, W.; Kawalla, Rudolf; Lehnert, F.

doi:10.1002/3527607552.ch98

Cited by 7 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The grain size gradually increased with increasing test temperature, the increase being faster beyond the temperature for the peak efficiency (450°C). The variation of the torsion ductility recorded by several investigators [19][20][21][22][23][24] exhibited a similar trend and as an example the data obtained by Chabbi and Lehnert [23] is shown in Figure 5(a). Such features are typical of the occurrence of DRX, which imparts high ductility at the peak efficiency.…”

Section: Processing Mapsupporting

confidence: 52%

“…The hot working behavior of Mg-Al-Zn alloys has been reviewed recently, [19] and the apparent activation energy estimated by different investigators has shown some variations and is generally higher than that for self-diffusion. [20][21][22][23][24] The aim of the present investigation is to characterize the hot deformation behavior of AZ31 rod produced by high temperature extrusion (HTX) (450°C) with a view to evaluate the hot working mechanisms and microstructural development in the product. Such a study would assist in achieving microstructural control during the secondary-forming stage of component manufacture in this industrially important magnesium alloy.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Hot Deformation Mechanisms and Microstructural Control in High‐Temperature Extruded AZ31 Magnesium Alloy

Prasad

Rao

2007

Adv Eng Mater

View full text Add to dashboard Cite

In recent years, magnesium alloys have attracted attention in view of their low density and high specific strength and are being considered for structural components in aerospace and automobile applications. [1] Out of the wrought magnesium alloys, Mg-3Al-1Zn (AZ31) is considered to be the work-horse and considerable emphasis is being given to develop processing-microstructure-mechanical property correlations for this alloy. [2][3][4][5][6][7][8][9][10][11] Since magnesium alloys have limited ductility at room temperature, forming is generally done at elevated temperatures, the most common method being extrusion. [12][13][14][15] AZ31 alloy is commercially extruded at a temperature of about 300°C, [12] which results in a fine grained microstructure and a fiber texture with <10 1 0>direction parallel to the extrusion direction (ED). [2,6] Deformation at higher temperatures would enhance the hot workability, even to the extent of resulting in superplasticity, [16][17][18] presumably due to extensive occurrence of pyramidal slip and dynamic recrystallization. In addition, higher extrusion temperatures result in an increase in grain size. [9] The hot deformation behavior of AZ31 alloy is sensitive to the initial microstructure and the prior processing history, [2,5,9] and both the above changes in grain size and texture will influence the hot workability of the extruded product. The hot working behavior of Mg-Al-Zn alloys has been reviewed recently, [19] and the apparent activation energy estimated by different investigators has shown some variations and is generally higher than that for self-diffusion. [20][21][22][23][24] The aim of the present investigation is to characterize the hot deformation behavior of AZ31 rod produced by high temperature extrusion (HTX) (450°C) with a view to evaluate the hot working mechanisms and microstructural development in the product. Such a study would assist in achieving microstructural control during the secondary-forming stage of component manufacture in this industrially important magnesium alloy. The hot deformation behavior is explored using the methods of kinetic analysis as well as processing maps. The former one is based on the standard kinetic rate equation relating the flow stress (r) to strain rate (_ e) and temperature (T), given by: [25] _ e Ar n expÀQ=RT (1) where A = constant, n = stress exponent, Q = activation energy, and R = gas constant. The rate-controlling mechanisms are identified on the basis of the activation parameters n and Q. The technique of processing maps is based on the dynamic materials model, the principles of which are described earlier. [26][27][28] Briefly, the work-piece undergoing hot deformation is considered to be a dissipator of power and the strain rate sensitivity (m) of flow stress is the factor that partitions power between deformation heat and microstructural changes. The efficiency of power dissipation occurring through microstructural changes during deformation is derived by comparing the non-linear power dissipation occurring instant...

show abstract

Section: Processing Mapsupporting

confidence: 52%

mentioning

confidence: 99%

Hot Deformation Mechanisms and Microstructural Control in High‐Temperature Extruded AZ31 Magnesium Alloy

Prasad

Rao

2007

Adv Eng Mater

View full text Add to dashboard Cite

show abstract

“…The rate-controlling mechanisms are identified on the basis of the activation parameters n and Q. The kinetics of hot working in Mg-Al-Zn alloys has been reviewed recently [21] and the apparent activation energy values estimated by different investigators [22][23][24][25][26] have shown some variations and are generally higher than that for lattice self-diffusion in magnesium.…”

Section: Introductionmentioning

confidence: 99%

Hot Deformation Mechanisms in AZ31 Magnesium Alloy Extruded at Different Temperatures: Impact of Texture

Rao

Prasad²,

Dzwonczyk

et al. 2012

Metals

View full text Add to dashboard Cite

Abstract:The hot deformation characteristics of AZ31 magnesium alloy rod extruded at temperatures of 300 °C, 350 °C and 450 °C have been studied in compression. The extruded material had a fiber texture with > < 0 1 10 parallel to the extrusion axis. When extruded at 450 °C, the texture was less intense and the > < 0 1 10 direction moved away from the extrusion axis. The processing maps for the material extruded at 300 °C and 350 °C are qualitatively similar to the material with near-random texture (cast-homogenized) and exhibited three dynamic recrystallization (DRX) domains. In domains #1 and #2, prismatic slip is the dominant process and DRX is controlled by lattice self-diffusion and grain boundary self-diffusion, respectively. In domain #3, pyramidal slip occurs extensively and DRX is controlled by cross-slip on pyramidal slip systems. The material extruded at 450 °C exhibited two domains similar to #1 and #2 above, which moved to higher temperatures, but domain #3 is absent. The results are interpreted in terms of the changes in > < 0 1 10 fiber texture with extrusion temperature. Highly intense > < 0 1 10 texture, as in the rod extruded at 350 °C, will enhance the occurrence of prismatic slip in domains #1 and #2 and promotes pyramidal slip at temperatures >450 °C (domain #3).

show abstract

“…[16] In Domain 3, the grain size is large, and its variation with strain rate at 550 8C (Figure 5c) shows that the grain size decreases with increasing strain rate, as typically observed in DRX. The torsional ductility measured at these temperatures is large, [25] and the stress-strain curves are of steady-state type, both of which suggest DRX. As we approach the region of flow instability, the grain size tends to increase with increase in strain rate.…”

Section: Processing Mapmentioning

confidence: 99%

Hot Workability, Microstructural Control and Rate‐Controlling Mechanisms in Cast‐Homogenized AZ31 Magnesium Alloy

Prasad

Rao

2009

Adv Eng Mater

View full text Add to dashboard Cite

Hot and Cold Forming Behaviour of Magnesium Alloys AZ31 and AZ61

Cited by 7 publications

References 0 publications

Hot Deformation Mechanisms and Microstructural Control in High‐Temperature Extruded AZ31 Magnesium Alloy

Hot Deformation Mechanisms and Microstructural Control in High‐Temperature Extruded AZ31 Magnesium Alloy

Hot Deformation Mechanisms in AZ31 Magnesium Alloy Extruded at Different Temperatures: Impact of Texture

Hot Workability, Microstructural Control and Rate‐Controlling Mechanisms in Cast‐Homogenized AZ31 Magnesium Alloy

Contact Info

Product

Resources

About