Microstructure and Superplasticity of an Al-Mg-Sc-Zr Alloy Processed by ECAP and Subsequent Cold Rolling

2015 ◽  
Vol 830-831 ◽  
pp. 345-349 ◽  
Author(s):  
Elena Avtokratova ◽  
Oleg Sitdikov ◽  
Oksana Mukhametdinova ◽  
Michael Markushev ◽  
S.V.S. Narayana Murty ◽  
...  
Keyword(s):  
Cold Rolling ◽  
High Strain Rate ◽  
Ambient Temperature ◽  
Strain Rate ◽  
Equal Channel Angular Pressing ◽  
High Strain ◽  
Strain Rates ◽  
Angular Pressing ◽  
Zr Alloy

The feasibility has been demonstrated for achieving high-strain-rate superplasticity with elongations beyond 2000% in Al-Mg-Sc-Zr alloy with the partially recrystallized structure, produced by warm equal-channel angular pressing to strain of e~3 only. Subsequent alloy ambient temperature rolling up to e~1.6 enhanced the superplastic elongations and moved the optimum of superplasticity toward the higher strain rates.

Extraordinary High Strain Rate Superplasticity of an Al-Mg-Sc-Zr Alloy Subjected to Equal Channel Angular Pressing

2012 ◽  
Vol 735 ◽  
pp. 295-300
Author(s):  
Elena Avtokratova ◽  
Oleg Sitdikov ◽  
Michael Markushev ◽  
Radik R. Mulyukov
Keyword(s):  
Strain Rate ◽  
Equal Channel Angular Pressing ◽  
High Strain ◽  
Strain Rate Range ◽  
Rate Range ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Excess Phases ◽  
Ultrafine Grained Microstructure ◽  
Zr Alloy

Unique superplastic elongations up to 4100% were achieved at 450°C in the strain rate range of 10-2-10-1s-1for Al-Mg-Sc-Zr alloy with a grain size ~1 μm processed by warm-to-hot equal channel angular pressing. Such a behavior is attributed to the synergy of complementary factors resulted in high homogeneity and stability of ultrafine-grained microstructure and superplastic flow, involving large proportion of high-angle grain boundaries, presence of dispersoids of aluminides of transition metals and negligible amount of coarse excess phases.

HIGH STRAIN-RATE PROPERTIES OF TANTALUM PROCESSED BY EQUAL CHANNEL ANGULAR PRESSING

2008 ◽  
Author(s):  
P. J. Flater ◽  
J. W. House ◽  
J. M. O'Brien ◽  
W. F. Hosford ◽  
Mark Elert ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Equal Channel Angular Pressing ◽  
High Strain ◽  
Angular Pressing

The Dynamic Behavior of Ultra-Fine-Grained Copper Fabricated by Equal Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 891-896
Author(s):  
Yue Cheng Dong ◽  
Igor V. Alexandrov ◽  
Jing Tao Wang
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Equal Channel Angular Pressing ◽  
High Strain ◽  
Maximum Yield ◽  
Coarse Grained ◽  
Static Compression ◽  
Fine Grained ◽  
Angular Pressing ◽  
High Strain Rate Deformation

The high-strain-rate response of ultra-fine-grained (UFG) copper fabricated by equal channel angular pressing (ECAP) has been characterized by Split Hopkinson Pressure Bar (SHPB) test and quasi-static compression test has also been performed for comparison here. In the result of quasi-static tests a maximum yield stress equal to 432 MPa has been reached, at the same time the corresponding value turned out to be 995 MPa after a dynamic loading with the strain rate equal to 1700 s-1. It has been demonstrated that the strain rate sensitivity coefficient (m) has enhanced from 0.026 (coarse-grained copper) to 0.037 (UFG copper). Microstructure has indicated a high dislocation density and deformation twins inside the grains formed after a high-strain-rate deformation, which resulted in a high flow stress. The occurrence of a dynamic recrystallization has also been observed in the UFG copper subjected to high-strain-rate deformation. This has become apparent as an accelerated thermal softening and inherent instability typical for the UFG structure. Absence of adiabatic shear bands pointed out that UFG copper can be subjected to a dynamic impact without any fracture.

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