Application of High-Strain-Rate Superplastic Zn-Al Alloy to Seismic Dampers and its Optimised Shape Design

2007 ◽  
Vol 551-552 ◽  
pp. 583-590 ◽  
Author(s):  
Atsumichi Kushibe ◽  
Yorinobu Takigawa ◽  
Kenji Higashi ◽  
Kazuo Aoki ◽  
Koichi Makii ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Work Hardening ◽  
Tall Buildings ◽  
High Energy ◽  
Local Deformation ◽  
Al Alloys ◽  
Optimum Shape ◽  
Al Alloy ◽  
Seismic Damper ◽  
Damping Material

As a new damping material, the authors first developed a Zn-22wt.%-Al eutectoid alloy with ultra-fine grains exhibiting superplasticity at room temperature by means of thermomechanical controlling processes (TMCPs). The Zn-Al alloy has a few advantages such as low work-hardening rate and high ductility over a conventional seismic damping material, for instance, a low-yield-point steel. In addition, Zn-Al alloys are environment-conscious because of no harmful metal like Pb. However, when Zn-Al alloys are subjected to plastic deformation, since its work hardening is small, plastic deformation proceeds locally so that required absorption energy cannot be sufficiently obtained, and local fracture and local deformation instability can take place easily, which is the intrinsic characteristic of superplastic materials. Therefore we attempted to develop a shear panel type, a brace type damper for tall buildings and a bending type damper for Japanese wooden houses using FEM analysis in order to minimize localized strain and local deformation and to determine the optimum shape for this Zn-Al superplastic seismic damper. As a result, an ecological and high-energy absorption seismic dampers, so-called “maintenance-free seismic damper,” was successfully developed.

Application to Seismic Dampers in High-Strain-Rate Superplastic Zn-Al Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 3055-3060 ◽  
Author(s):  
Atsumichi Kushibe ◽  
Koichi Makii ◽  
L.F. Chiang ◽  
Tsutomu Tanaka ◽  
Masahide Kohzu ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Work Hardening ◽  
High Performance ◽  
High Strain ◽  
Al Alloys ◽  
Al Alloy ◽  
Seismic Damper ◽  
Fine Grained ◽  
Work Hardening Rate

High strain rate superplasticity has been realised at room temperature for the first time with a ultra fine grained Zn-22wt%Al alloy. Zn-Al alloys have some advantages over low-yieldpoint steels in their low work-hardening rate and high ductility. In addition, Zn-Al alloys are environment-conscious because of no harmful metal like Pb. However, when Zn-Al alloys are subjected to plastic deformation, the strain is localised and local fracture can take place because of their low work-hardening property. In this study, a seismic damper was designed with a Ultra fine grained Zn-Al alloy. As a result, an ecological and high performance seismic damper, the so-called “maintenance-free seismic damper”, has been successfully developed.

Microstructural Change of Beta Type Titanium Alloy by Intense Plastic Deformation

2006 ◽  
Vol 503-504 ◽  
pp. 705-710 ◽  
Author(s):  
Goroh Itoh ◽  
Hisashi Hasegawa ◽  
Tsing Zhou ◽  
Yoshinobu Motohashi ◽  
Mitsuo Niinomi
Keyword(s):  
Plastic Deformation ◽  
Work Hardening ◽  
Static Recrystallization ◽  
True Strain ◽  
Microstructural Change ◽  
Intense Plastic Deformation ◽  
Rolled Plate ◽  
Al Alloy ◽  
Hot Rolled ◽  
Zr Alloy

Usual static recrystallization treatment and a method to provide intense plastic deformation, ARB namely Accumulative Roll-Bonding, have been applied to two beta type titanium alloys, i.e. Ti-29Nb-13Ta-4.6Zr and Ti-15V-3Cr-3Sn-3Al. Microstructural change as well as work-hardening behavior was examined as a function of plastic strain. Both the work-hardening rate and the hardness at the initial as-hot-rolled state were smaller in the Ti-Nb-Ta-Zr alloy than in the Ti-V-Cr-Sn-Al alloy. Recrystallized grains of 14μm in size were obtained by the usual static recrystallization treatment, which was significantly smaller than that of the starting as-hot-rolled plate of 38μm. No significant change other than flattening and elongating of the original grains was found in the optical microscopic scale. It was revealed, however, from a TEM observation combined with selected area diffraction technique that geometric dynamic recrystallization occurred in the Ti-Nb-Ta-Zr alloy deformed at room temperature by a true strain of 5, resulting in an ultra-fine-grained microstructure where the grain size was roughly estimated to be about 100nm.

Estimation of Crystalline Size of Deformed 5251 Al Alloy Using PALT and XRD Techniques

2013 ◽  
Vol 337-338 ◽  
pp. 11-18
Author(s):  
M. Abdel-Rahman ◽  
Ahmed G. Attallah ◽  
M. El-Sayed ◽  
A.A. Ibrahim ◽  
A.A. Akel ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Al Alloys ◽  
Radioactive Isotopes ◽  
Crystalline Size ◽  
Al Alloy ◽  
Solid Materials ◽  
Deformation Effect ◽  
Powerful Technique ◽  
Xrd Techniques

Certain radioactive isotopes decay by emitting positrons, and the positrons can be used to probe the structure of solid materials. For example, one can investigate the grain size due to deformation in a metal. XRD is also a powerful technique for detection the defects introduced into a metal and for investigating the microstructure of a deformed metal. In this paper we shall investigate the plastic deformation effect on the grain size of 5251 Al alloys using two different techniques, PALT and XRD. The study shows a significant effect of the plastic deformation on the grain size which decreases as the deformation increases.

The Relationship between Mg Content and Extra-Hardening in Ultrafine Grained Al-Mg Alloy by SPD

2018 ◽  
Vol 941 ◽  
pp. 1173-1177
Author(s):  
Yuto Suzuki ◽  
Yuichi Shiono ◽  
Taiki Morishige ◽  
Toshihide Takenaka
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Work Hardening ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Mg Alloy ◽  
Al Alloy ◽  
Ultrafine Grained ◽  
Mg Content ◽  
The Relationship

Severe Plastic Deformation (SPD) process is one of methods for obtaining UFG-Al. It was reported in SPD-processed Al alloy that the extra-hardening due to work hardening caused by accumulated dislocation in the grains. In Al-Mg alloy, Mg decreases the stacking fault energy in this alloy, and dislocation tends to accumulate in the grains. In this study, Al-Mg alloy with various Mg contents were processed by Equal-Channel Angular Pressed (ECAP) which was one of SPD and annealed after processed ECAP. The relationship between Mg content and magnitude of extra-hardening was investigated. In ECAPed Al-3mass%Mg alloy, it was thought that extra-hardening was caused. Magnitude of extra-hardening was increased with increasing Mg content.

Formation of Al-Ti-B Phases for Grain Refinement of Al Alloys Produced by High Energy Ball Milling

2017 ◽  
Vol 907 ◽  
pp. 188-192
Author(s):  
Mesut Arikoğlu ◽  
Fatih Apaydın ◽  
Ali Özer
Keyword(s):  
Grain Refinement ◽  
Ball Mill ◽  
High Energy ◽  
Al Alloys ◽  
Planetary Ball Mill ◽  
Al Alloy ◽  
Elemental Distribution ◽  
Distribution Analysis ◽  
Alloy Series ◽  
Grain Formation

In this experimental study, Al-Ti-B powders were ground in planetary ball mill to produce AlxTiyBz where x, y and z stands for the relative molar ratios of elements for the compilation of grain refiner compound. Powder size distribution, phase formation (XRD) and particle morphology was investigated by means of SEM and XRD. The fabrication of AlTiB phases and the grain refinement of Al alloys by adding this phase were aimed. For this purpose, the powders were fed to planetary ball mill to be milled at a speed of 600 rpm. The powders were also milled at different milling times as 30 min and 150 min either in metallic form or compound form of Al, Ti and B powders. The powders were dried after each milling to be characterized by SEM and XRD. The phases and morphology-elemental analysis were also conducted by XRD and SEM, respectively. Moreover, the powders were added to Al alloy castings avoiding the breaking through alloy series which are mainly used in aluminum industry. The Al alloy series were examined for grain refinement by Brinell hardness and optical microscopy for mechanical properties and grain formation as well as by SEM (EDS) for grain formation, morphology and elemental distribution analysis.

Processing of Cu-Al-Ni and Cu-Zn-Al Alloys by Mechanical Alloying

2012 ◽  
Vol 727-728 ◽  
pp. 200-205 ◽  
Author(s):  
André Victor Traleski ◽  
Selauco Vurobi Jr. ◽  
Osvaldo Mitsuyuki Cintho
Keyword(s):  
Mechanical Alloying ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Weight Ratio ◽  
High Energy ◽  
Al Alloys ◽  
Al Alloy ◽  
Second Phase ◽  
Metal Powders

The mechanical alloying process provides alloys with extremely refined microstructure, reducing the need for alloying elements to grain growth restriction, as in casting techniques. The Cu-Al-Ni and Cu-Zn-Al alloys produced by casting may have the shape memory effect when plastically deformed at relatively low temperatures, returning to its original shape upon heating at a given temperature. This work aimed at the production of Cu-Al-Ni and Cu-Zn-Al alloys by mechanical alloying, followed by microstructural characterization and investigation of the shape memory effect by means of differential scanning calorimetry (DSC). Metal powders of Cu, Al, Ni and Cu, Zn, Al were processed in a SPEX high energy vibratory mill during 8 hours, with ball-to-powder weight ratio of 5:1. The milled products were characterized by X-ray diffraction. For each alloy, specimens with 8 mm diameter and 2 mm thickness were shapes by uniaxial pressing, sintered in a tube furnace with argon atmosphere, solubilized and then quenched in water. Samples were characterized by optical and scanning electron microscopy (SEM), Vickers hardness testing and DSC. An ultrafine microstructure was obtained in the Cu-Al-Ni alloy but the shape memory effect was not detected by DSC analysis because of second phase precipitation. The shape memory effect was not present in the Cu-Zn-Al alloy also, because of zinc oxidation during the sintering.

Deformation Mechanisms and Ductility of Nanostructured Al Alloys

2004 ◽  
Vol 821 ◽  
Author(s):  
Bing Q. Han ◽  
Farghalli A. Mohamed ◽  
Enrique J. Lavernia
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Aluminum Alloys ◽  
Severe Plastic Deformation ◽  
Work Hardening ◽  
Tensile Ductility ◽  
High Strength ◽  
Al Alloys ◽  
Deformation Mechanisms ◽  
Coarse Grains

AbstractLow tensile ductility is one of the critical challenges facing the science and technology of nanostructured materials. As an example, despite the fact that high strength is frequently observed in bulk nanostructured Al alloys, ductility and work hardening are often observed to decrease with decreasing grain size. In the present study, the tensile ductility of bulk nanostructured aluminum alloys processed via severe plastic deformation and consolidation of mechanically milled powders is analyzed. Adding coarse grains to the nanostructured matrix is proposed as an approach to improve ductility.

scholarly journals Influence of microstructure evolution during thermal aging on tensile properties of β-type Ti-12V-2Fe-Al alloy

2020 ◽  
Vol 321 ◽  
pp. 11072
Author(s):  
Weilin Wang ◽  
Xianbing Zhang ◽  
Jian Sun
Keyword(s):  
Plastic Deformation ◽  
Tensile Properties ◽  
Aging Temperature ◽  
Deformation Mode ◽  
Al Alloys ◽  
Dislocation Slip ◽  
Al Alloy ◽  
Β Phase ◽  
Ω Phase ◽  
Stabilization Effect

The evolution of the ω phase and its influence on tensile properties in β Ti-12V-2Fe-1Al alloys aged at temperature from 373 to 573 K were investigated. The results show that the formation of the thermal ω phase starts to take place at temperature between 393 and 423 K in the alloy. The growth of the thermal ω particles is accompanied by a rejection of V, Fe and Al solute atoms from the growing thermal ω particles into the surrounding β matrix. Tensile properties of the β Ti-12V-2Fe-Al alloy are strongly dependent on aging temperature. The plastic deformation mode changes from fully {332} deformation twinning in the ST alloy, to dislocation slip mixed with partially {332} twinning in the alloy aged at 393 K and to dislocation slip associated with stress-induced ω phase transformation in the alloy aged at 423 K. Particularly, the alloys aged at 523 K and above exhibit a brittle fracture without any elongation. It is suggested that the occurrence of the coherent elastic strain between the ω and β phase results in stabilization effect on the β matrix, which may account for the drastic change in plastic deformation mode and tensile properties in aged Ti-12V-2Fe-Al alloys with an increase of aging temperature.

Study the Effect of Plastic Deformation in 8006 Al-Alloys by Positron Lifetime Spectroscopy, Vickers Hardness and X-Ray Diffraction

2017 ◽  
Vol 373 ◽  
pp. 142-145 ◽  
Author(s):  
Emad A. Badawi ◽  
M.A. Abdel-Rahman ◽  
Mohammed Salah ◽  
Mohamed Abdel-Rahman
Keyword(s):  
Plastic Deformation ◽  
Vickers Hardness ◽  
Positron Lifetime ◽  
Positron Annihilation Spectroscopy ◽  
Al Alloys ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Degree Of Deformation ◽  
X Ray ◽  
Positron Lifetime Spectroscopy

Due to the great effect of defects on the properties of the material including strength, ductility, resistivity and opacity, there are many techniques that are used in defect detecting. Positron annihilation spectroscopy (PAS), Vickers hardness, and X-ray diffraction were used to study the influence of plastic deformation on the properties of 8006 Al-alloy in this work. An increase in the positron lifetime and Vickers hardness with a bit Broadening of XRD peaks was observed with increasing the degree of deformation reflecting a large dislocation density produced by plastic deformation.

Electron microscopy study of shock synthesis of silicides

1993 ◽  
Vol 51 ◽  
pp. 1162-1163
Author(s):  
Kenneth S. Vecchio
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Close Contact ◽  
Microscopy Study ◽  
High Energy ◽  
Electron Microscopy Study ◽  
Powder Materials ◽  
Porous Powder ◽  
Wave Effects ◽  
Wave Passage

Shock-induced reactions (or shock synthesis) have been studied since the 1960’s but are still poorly understood, partly due to the fact that the reaction kinetics are very fast making experimental analysis of the reaction difficult. Shock synthesis is closely related to combustion synthesis, and occurs in the same systems that undergo exothermic gasless combustion reactions. The thermite reaction (Fe2O3 + 2Al -> 2Fe + Al2O3) is prototypical of this class of reactions. The effects of shock-wave passage through porous (powder) materials are complex, because intense and non-uniform plastic deformation is coupled with the shock-wave effects. Thus, the particle interiors experience primarily the effects of shock waves, while the surfaces undergo intense plastic deformation which can often result in interfacial melting. Shock synthesis of compounds from powders is triggered by the extraordinarily high energy deposition rate at the surfaces of the powders, forcing them in close contact, activating them by introducing defects, and heating them close to or even above their melting temperatures.

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