Superplasticity of Nickel-Based Alloys with Micro- and Sub-Microcrystalline Structures

1999 ◽  
Vol 601 ◽  
Author(s):  
V.A. Valitov ◽  
B.P. Bewlay ◽  
Sh. Kh. Mukhtarov ◽  
O.A. Kaibyshev ◽  
M.F.X. Gigliotti
Keyword(s):  
Grain Size ◽  
Low Temperature ◽  
High Strain Rate ◽  
Static Recrystallization ◽  
High Strain ◽  
Coarse Grained ◽  
Superplastic Behavior ◽  
Ni Alloys ◽  
Alloy Chemistry ◽  
The Relationship

AbstractThis paper will describe the generation of micro- and sub-microcrystalline structures in two Ni-based alloys that are typically strengthened by phases, such as γ′ and γ″+δ. The relationship between the superplastic behavior and microstructure will be discussed. High strain deformation processing in the temperature range of 0.9 Tm to 0. 6Tm results in reduction of the initial coarse-grained structure (>100 µm) to a range of structures including microcrystalline (MC) (grain size <10 µm) and sub-microcrystalline (SMC) (grain size <1 µm) with increasing deformation. The influence of alloy chemistry and constituent phases on dynamic and static recrystallization is considered, and their effect on grain refinement is described. Low-temperature and high strain rate superplasticity can be observed in dispersionstrengthened alloys with SMC structures. It was established that in dispersion-hardened Ni alloys with SMC structures, superplasticity can be observed at temperatures 200-250°C lower than in alloys with MC structure.

Factors Effect on Grain Refining of Nanocrystalline Copper Fabricated by Explosive Loading and its Dynamic Mechanical Property

2010 ◽  
Vol 150-151 ◽  
pp. 1530-1536
Author(s):  
Jin Xiang Wang ◽  
Nan Zhou ◽  
Zheng Zhao
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Coarse Grained ◽  
Grain Refining ◽  
Nanocrystalline Copper ◽  
Dynamic Mechanical ◽  
Average Grain Size

By the method of severe plastic deformation at high strain rate of coarse-grained copper under explosively dynamic loading, nanocrystalline(NC) copper was fabricated. The deformation process were simulated recur to Ls-Dyna3d finite element program , the effects of the strain on the degree of grain-refining were analysed. Finally, the dynamic mechanical properties of the NC copper were researched recur to split Hopkinson pressure bar(SHPB). The results show that it is feasible to fabricate nanocrystalline copper by explosively dynamic plastic deformation of coarse-grained copper and the grain size of the NC copper can be controlled less than 100 nanometer; higher strain at high strain rate is beneficial to the grain refining; the distribution of the grain size is not uniform along the loading direction; dynamic yield strength of the NC copper enhences with the decreasing of the average grain size and increasing of the strain rate.

Tensile Ductility of Ultra-Fine Grained Copper at High Strain Rate

2010 ◽  
Vol 160-162 ◽  
pp. 260-266 ◽  
Author(s):  
Tao Suo ◽  
Kui Xie ◽  
Yu Long Li ◽  
Feng Zhao ◽  
Qiong Deng
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Testing Machine ◽  
Coarse Grained ◽  
Dislocation Dynamic ◽  
Pressing Method ◽  
Fine Grained ◽  
Angular Pressing ◽  
Split Hopkinson

In this paper, ultra-fine grained copper fabricated by equal channel angular pressing method and annealed coarse grained copper were tensioned under both quasi-static and dynamic loading conditions using an electronic universal testing machine and the split Hopkinson tension bar respectively. The rapture surface of specimen was also observed via a Scanning Electron Microscope (SEM). The experimental results show that the ductility of polycrystalline copper decreases remarkably due to the grain refinement. However, with the increase of applied strain rate, ductility of the UFG-Cu is enhanced. The fracture morphologies also give the evidence of enhanced ductility of UFG-Cu at high strain rate. It is believed the enhanced ductility of UFG materials at high strain rate can be attributed to the restrained dislocation dynamic recovery.

Microstructural Design for Attaining High-Strain-Rate Superplasticity in Oxide Materials

2006 ◽  
Vol 45 ◽  
pp. 923-932
Author(s):  
Keijiro Hiraga ◽  
Byung Nam Kim ◽  
Koji Morita ◽  
Tohru Suzuki ◽  
Yoshio Sakka
Keyword(s):  
Grain Size ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Spinel Phase ◽  
Tetragonal Zirconia ◽  
Secondary Phases ◽  
Cavitation Damage ◽  
Size Refinement ◽  
Dynamic Grain Growth

Factors limiting the strain rate of superplastic deformation in oxide ceramics are discussed from existing knowledge about the mechanisms of high-temperature plastic deformation and intergranular cavitation. The discussion leads to the following guide: simultaneously controlling the initial grain size, diffusivity, dynamic grain growth, homogeneity of microstructure and the number of residual defects is essential to attain high-strain-rate superplasticity. Along this guide, high-strain-rate superplasticity (HSRS) is attainable in some oxides consisting of tetragonal zirconia, α-alumina and a spinel phase: tensile ductility reached 300-2500% at a strain rate of 0.01-1.0 s-1. Post-deformation microstructure indicates that some secondary phases may suppress cavitation damage and thereby enhance HSRS. The guide is also essential to lower the limit of deformation temperature for a given strain rate. In monolithic tetragonal zirconia, grain-size refinement combined with doping of aliovalnt cations such as Mg2+, Ti4+ and Al3+ led to HSRS at 1350 °C.

High Strain Rate Blow Formability of Newly Developed Al-Mg-High-Mn Alloy

2012 ◽  
Vol 735 ◽  
pp. 271-277 ◽  
Author(s):  
Tomoyuki Kudo ◽  
Akira Goto ◽  
Kazuya Saito
Keyword(s):  
Grain Size ◽  
High Strain Rate ◽  
Strain Rate ◽  
Mass Production ◽  
High Strain ◽  
Mg Alloy ◽  
Strain Rates ◽  
Fine Grain ◽  
Aa5083 Alloy ◽  
Complex Parts

Blow forming accompanied with superplasticity makes possible the forming of complex parts, which cannot be formed by cold press forming. The conventional superplastic AA5083 alloy ‘ALNOVI-1’ developed by the Furukawa-Sky Aluminum Corp. shows high superplasticity because of its fine grain and is widely used for blow forming. However, for mass production of components, an Al-Mg alloy with finer-sized grains is needed. In this research, the newly developed high Mn version of the Al-Mg alloy ‘ALNOVI-U’ is used, and this material possesses grains finer than those of the conventional AA5083 alloy. The effects of finer grain size on the blow formability at high strain rates over 10-2/s and the properties of the resulting moldings were studied.

Low-Temperature and High-Strain Rate Superplastic Zirconia

2003 ◽  
Vol 5 (3) ◽  
pp. 130-133 ◽  
Author(s):  
Y. Sakka ◽  
T. Matsumoto ◽  
T.S. Suzuki ◽  
K. Morita ◽  
B.-N. Kim ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain

scholarly journals Low Temperature and High Strain Rate Superplasticity of Ni-1 mass%SiC Nanocomposite

2004 ◽  
Vol 45 (8) ◽  
pp. 2558-2563 ◽  
Author(s):  
K.C. Chan ◽  
C.L. Wang ◽  
K.F. Zhang
Keyword(s):  
Low Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain

High Strain Rate Superplasticity and Microstructure Evolution in a Coarse-Grained Mg-Gd-Y-Zr Rolled Sheet

2014 ◽  
Vol 900 ◽  
pp. 719-724
Author(s):  
Ying Zheng ◽  
Chang Ping Tang ◽  
Yun Lai Deng
Keyword(s):  
Electron Microscopy ◽  
Dynamic Recrystallization ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Microstructural Analysis ◽  
Alloy Sheet ◽  
Coarse Grained ◽  
Dislocation Slip ◽  
Rolled Sheet

Superplasticity at high deformation rates is desirable in order to make superplastic forming more practical. High strain rate superplastic behavior and microstructure of the rolled Mg-Gd-Y-Zr alloy sheet were investigated. For the purposes, tensile tests at the strain rate of 0.01 s-1were conducted, which revealed that the sheet exhibited elongations of 180%~266%. Post-deforming microstructures were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy, while crystallographic orientation information was obtained from macro-texture analysis. The results show that the high strain rate superplasticity was attributed to class-I creep accommodated by dynamic recrystallization. It is suggested from microstructural analysis results that the interaction between second phases and dislocation facilitated dynamic recrystallization. The macro-texture at the strain of 0.8 still exhibited some characteristics of the crystal rotation arising from dislocation slip despite the occurrence of DRX.

Using Extrusion and ECAP Processing to Achieve Low Temperature and High Strain Rate Superplasticity

2003 ◽  
Vol 419-422 ◽  
pp. 497-502 ◽  
Author(s):  
Kiyoshi Matsubara ◽  
Yuichi Miyahara ◽  
Koichi Makii ◽  
Z. Horita ◽  
Terence G. Langdon
Keyword(s):  
Low Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Ecap Processing

scholarly journals Investigation on grain size effect in high strain rate ductility of 1100 pure aluminum

2017 ◽  
Author(s):  
N. Bonora ◽  
N. Bourne ◽  
A. Ruggiero ◽  
G. Iannitti ◽  
G. Testa
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Pure Aluminum ◽  
Grain Size Effect
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