Steady State Deformation and Dynamic Restoration Processes During High Strain Rate and High Temperature Deformation in Metals and Alloys

1979 ◽  
pp. 108-119
Author(s):  
T. Nakamura
Keyword(s):  
Steady State ◽  
High Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Metals And Alloys ◽  
High Temperature Deformation ◽  
Temperature Deformation

High Strain Rate Deformation Behavior of Mg–Al–Zn Alloys at Elevated Temperatures

2007 ◽  
Vol 340-341 ◽  
pp. 107-112 ◽  
Author(s):  
Hiroyuki Watanabe ◽  
Koichi Ishikawa ◽  
Toshiji Mukai
Keyword(s):  
High Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Elevated Temperatures ◽  
High Strain ◽  
Strain Rate Range ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Rate Range

High temperature deformation behavior of AZ31 and AZ91 magnesium alloys was examined by compression tests over a wide strain rate range from 10–3 to 103 s–1 with emphasis on the behavior at high strain rates. The dominant deformation mechanism in the low strain rate range below 10–1 s–1 was suggested to be climb-controlled dislocation creep. On the other hand, experimental results indicated that the deformation at a high strain rate of ~103 s–1 proceeds by conventional plastic flow of dislocation glide and twinning even at elevated temperatures. The solid-solution strengthening was operative for high temperature deformation at ~103 s–1.

Significance of High Rate Superplasticity in Metallic Materials

1990 ◽  
Vol 196 ◽  
Author(s):  
Norio Furushiro ◽  
Shigenori Hori
Keyword(s):  
Grain Size ◽  
High Strain Rate ◽  
Strain Rate ◽  
Grain Refinement ◽  
Fine Particles ◽  
High Strain ◽  
High Rate ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Al Alloy

ABSTRACTIt has been expected that “High rate superplastic materials” will be developed for industrial applications. The Dorntype equation for high temperature deformation suggests that strain rate can be increased if the grain size is decreased. This means that grain refinement can effectively establish high strain rate superplastic materials.It is well known that a high degree of grain size refinement will result from the addition of zirconium to Al-base alloys. Powder-metallurgical processing with rapidly solidified powders is also available for the improvement of superplasticity by both the refinement of the solidified structure and the maintenance of the stable fine structure of a 7475 Al alloy during recrystallization and deformation. Therefore. P/M 7475 Al alloys containing Zr up to 0.9 wt% were selected as candidate specimens. The objective of the present paper includes the clarification of the role and the effective amount of Zr to obtain high strain rate superplastic materials. As a result, the addition of 0.3%Zr or more is effective in grain refinement of the P/M 7475 Al alloy. However, alloys containing 0.7 and 0.9 wt%Zr only show superplasticity at 793K. The optimum strain rate is shifted to a higher range with increasing Zr. The alloy of 7475 Al-0.9%Zr shows the maximum elongation of 900% at the remarkably high strain rate of 3.3×10−1 s−1.The deformation mechanism of such high stain rate superplasticity will be discussed briefly, by considering the effect of the fine particles of Zr on superplastic behavior.

Modelling and Analysis of High Strain Rate Deformation at Elevated Temperature in Friction Stirring of Aluminum Alloys

2016 ◽  
Vol 838-839 ◽  
pp. 110-115
Author(s):  
Katsuya Kumai ◽  
Hiroki Fukushige ◽  
Yoshimasa Takayama
Keyword(s):  
Elevated Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Frictional Heat ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Friction Stir ◽  
Fine Grain ◽  
High Strain Rate Deformation

Friction stirring is a fundamental process in the friction stir welding (FSW), and moreover, high strain rate deformation in elevated temperature to lead to extremely high ductility and fine grain size. In the present study, friction stirring process has been successfully modelled as a high temperature deformation depending on strain rate and temperature, assuming shear deformation of material in stir zone and generation of frictional heat by rotating tool. Axial load and torque during the process were estimated based on the model, and compared with the experimental data at two kinds of combination ratio in FSW of aluminum and Al-Mg alloy. It was, consequently, confirmed that the model could evaluate flow stress and strain rate from the experimental load and torque.

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