Shape Memory Properties and Microstructure of New Iron-Based FeNiCoAlTiNb Shape Memory Alloys

The shape memory properties and microstructure of Fe41Ni28Co17Al11.5(Ti+Nb)2.5 (at.%) cold-rolled alloys were studied at the first time using the values reported in constant stress thermal cycling experiments in a three-point bending test. Thermo-magnetization curves of 97% cold-rolled and solution-treated sample aged at 600 °C for 24, 48 and 72 h showed evidence of the martensitic transformation, and the transformation temperatures increased their values from 24 to 72 h. The alloy cold-rolled to 97% and then solution-treated at 1277 °C for 1 h showed that most grains were aligned near <100> in the rolling direction in the recrystallization texture. The intensity of texture was 13.54, and an average grain size was around 400 μm. The sample aged at 600 °C for 48 h showed fully recoverable strain up to 1.6% at 200 MPa stress level in the three-point bending test. However, the experimental recoverable strain values were lower than the theoretical values, possibly due to the small volume fraction of low angle grain boundary, the formation of brittle grain boundary precipitates, and a grain boundary constraint lower than the expected intensity of texture in the samples.

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Grain Refinement of GH4169G Alloy by the Combination of Heat Treatment and Cold Deformation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.788.543 ◽

2014 ◽

Vol 788 ◽

pp. 543-548 ◽

Cited By ~ 2

Author(s):

Lin Jie Huang ◽

Feng Qi ◽

Wen Ru Sun ◽

Pei Tao Hua ◽

Fang Liu ◽

...

Keyword(s):

Grain Boundary ◽

Grain Refinement ◽

Cold Deformation ◽

Phase Precipitation ◽

Fine Grained ◽

Optimum Parameters ◽

Solution Treated ◽

Average Grain Size ◽

Δ Phase ◽

Cold Rolled

The precipitating behavior of δ phase in GH4169G alloy at 910°C was investigated and a novel process for achieving fine-grained GH4169G sheet with average grain size of ASTM13 was proposed. Globular δ phase precipitation precedes that of the plate-like δ phase, forming at grain boundary first and later in grain. After globular δ phase reaches a peak volume, it begins to transform into plate-like in grain boundary, and then the plate-like δ phase forms in grain in certain direction. The grain-fined process includes the following steps:(1) solution treated at a proper temperature, then air cooled; (2) soaked for δ phase precipitation; (3) cold rolled; (4) annealed for recrystallization. Microstructure analysis from optical microscopy (OM) and scanning electron microscopy (SEM) revealed that both plate-like and globular δ phase remarkably restrained the grain growth during annealing recrystallization. The optimum parameters for the grain refinement were determined finally.

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The Microstructure and Creep Behavior of Cold Rolled Udimet 188 Sheet

Microscopy and Microanalysis ◽

10.1017/s1431927610094225 ◽

2010 ◽

Vol 17 (3) ◽

pp. 350-361

Author(s):

C.J. Boehlert ◽

S.C. Longanbach

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Creep Behavior ◽

Volume Fraction ◽

Solution Treatment ◽

Tensile Creep ◽

Dislocation Creep ◽

Grain Boundary Character Distribution ◽

Air Cooling ◽

Cold Rolled

AbstractUdimet 188 was subjected to thermomechanical processing (TMP) in an attempt to understand the effects of cold-rolling deformation on the microstructure and tensile-creep behavior. Commercially available sheet was cold rolled to varying amounts of deformation (between 5–35% reduction in sheet thickness) followed by a solution treatment at 1,464 K (1,191°C) for 1 h and subsequent air cooling. This sequence was repeated four times to induce a high-volume fraction of low-energy grain boundaries. The resultant microstructure was characterized using electron backscattered diffraction. The effect of the TMP treatment on the high-temperature [1,033–1,088 K (760–815°C)] creep behavior was evaluated. The measured creep stress exponents (6.0–6.8) suggested that dislocation creep was dominant at 1,033 K (760°C) for stresses ranging between 100–220 MPa. For stresses ranging between 25–100 MPa at 1,033 K (760°C), the stress exponents (2.3–2.8) suggested grain boundary sliding was dominant. A significant amount of grain boundary cracking was observed both on the surface and subsurface of deformed samples. To assess the mechanisms of crack nucleation, in situ scanning electron microscopy was performed during the elevated-temperature tensile-creep deformation. Cracking occurred preferentially along general high-angle grain boundaries (GHAB) and less than 25% of the cracks were found on low-angle grain boundaries (LAB) and coincident site lattice boundaries (CSLB). Creep rupture experiments were performed at T = 1,088 K (815°C) and σ = 165 MPa and the greatest average time-to-rupture was exhibited by the TMP sheet with the greatest fraction of LAB+CSLB. However, a clear correlation was not exhibited between the grain boundary character distribution and the minimum creep rates. The findings of this work suggest that although grain boundary engineering may be possible for this alloy, simply relating the fraction of grain boundary types to the creep resistance is not sufficient.

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J Integral of Steel Fiber Reinforced High Strength Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.476-478.1568 ◽

2012 ◽

Vol 476-478 ◽

pp. 1568-1571

Author(s):

Ting Yi Zhang ◽

Guang He Zheng ◽

Ping Wang ◽

Kai Zhang ◽

Huai Sen Cai

Keyword(s):

High Strength Concrete ◽

Fiber Volume Fraction ◽

Steel Fiber ◽

Volume Fraction ◽

High Strength ◽

Bending Test ◽

Fiber Reinforced ◽

Fiber Volume ◽

Three Point Bending ◽

Strength Concrete

Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete (SFHSC), the effects of influencing factors including water-cement ratio (W/C) and the fiber volume fraction (ρf) upon the critical value(JC) of J integral were studied. The results show that the variation tendencies of JC are different under different factors. JC meets the linear statistical relation with W/C, ρf, respectively.

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Shape Memory Behavior of Ti-50.9at%Ni Alloy after ECAE Processes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.2313 ◽

2007 ◽

Vol 561-565 ◽

pp. 2313-2316 ◽

Cited By ~ 8

Author(s):

Zhi Guo Fan ◽

Chao Ying Xie

Keyword(s):

Phase Transformation ◽

Shape Memory ◽

Initial Solution ◽

Transformation Behavior ◽

Shape Memory Behavior ◽

Solution Treated ◽

Ni Alloy ◽

Coarse Grains ◽

Shape Memory Properties ◽

Before And After

The initial coarse grains of Ti-50.9at%Ni were obviously refined after eight ECAE processes. Effects of pressing number on the transformation behavior have been investigated in detail. Comparing with the initial solution-treated Ti-50.9at%Ni, the R-phase transformation was stimulated and the martensitic temperature Ms decreased with ECAE processes at 773K. The shape memory properties of Ti-50.9at%Ni alloy before and after ECAE processes at 773K have been measured. Good one way shape memory and superelasticity were obtained for the submicron-grained Ti-50.9at%Ni alloy.

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An Estimation of Joint Strength by Using Fe-Based Shape Memory Alloy Subjected to Bending Deformation at Various Deformation Rate

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.626.228 ◽

2014 ◽

Vol 626 ◽

pp. 228-233 ◽

Cited By ~ 2

Author(s):

Kazuki Fujita ◽

Keizo Nishikori ◽

Takeshi Iwamoto

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Deformation Rate ◽

Bending Strength ◽

Rate Sensitivity ◽

Force Balance ◽

Bending Test ◽

Structural Members ◽

Bending Deformation ◽

Three Point Bending

In various kinds of shape memory alloy (SMA), Fe-based SMA (Fe-SMA) shows smaller shape memory effect compared with the other SMAs. However, Fe-SMA shows huge advantages on the excellent formability, machinability, etc. Moreover, its production cost is cheaper than other SMAs; therefore, the alloy is attempted to be applied to structural members such as joints and dampers. Since bending deformation at higher deformation rate is generated in the members, especially the joints, due to impact force such as earthquake or wind, a clarification on the bending strength of the joints at various deformation rate is strongly required. In this study, at first, it is attempted that the bending strength and its rate sensitivity of the joints which consist of Fe-based SMA are experimentally estimated by the three-point bending test at various deformation rate. Then, the force balance equation is challenged to be derived to predict the bending strength.

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Martensitic Transformation and Mechanical Properties of Fe-added Au-Cu-Al Shape Memory Alloy with Various Heat Treatment Conditions

MRS Proceedings ◽

10.1557/opl.2014.949 ◽

2014 ◽

Vol 1760 ◽

Cited By ~ 2

Author(s):

Akira Umise ◽

Masaki Tahara ◽

Kenji Goto ◽

Tomonari Inamura ◽

Hideki Hosoda

Keyword(s):

Heat Treatment ◽

Cold Rolling ◽

Shape Memory ◽

Yield Stress ◽

Mechanical Treatment ◽

Tensile Tests ◽

Treatment Temperature ◽

Shape Memory Properties ◽

Cold Rolled ◽

Thermo Mechanical Treatment

ABSTRACTIn order to improve shape memory properties of Au-Cu-Al based shape memory alloys, the possibility to utilize thermo-mechanical treatment was investigated in this study, and effects of heat-treatment temperature on microstructure, martensitic transformation and mechanical properties of cold-rolled Au-30Cu-18Al-2Fe (AuCuAlFe) alloy were clarified by X-ray diffraction analysis (XRD, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and tensile tests at room temperature (RT). Here, Fe addition to AuCuAl improves ductility. Cold rolling with the thickness reduction of 30% was successfully carried out in AuCuAlFe at RT. An exothermic heat was observed in DSC at temperature from 402K, suggesting that recovery started at 402K. Besides, the transformation temperature hysteresis increased by the cold-rolling. The alloy was completely recrystallized after the heat treatment at 573K for 3.6ks. Tensile tests revealed that the yield stress was raised by cold rolling and largely by the subsequent heat treatment at 433K, which corresponded to the recovery start temperature by DSC. The yield stress decreased with increasing heat treatment temperature over 453K, probably due to recrystallization. AuCuAlFe cold-rolled and subsequent heat-treated at 573K exhibited the lowest yield stress as well as stress-plateau region, indicating that the thermo-mechanical treatment is effective to improve shape memory properties of Au-Cu-Al based alloys.

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Fracture Characterization of MoSi2 Based Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.261-263.1481 ◽

2004 ◽

Vol 261-263 ◽

pp. 1481-1486 ◽

Cited By ~ 1

Author(s):

Sang Ll Lee ◽

J.O. Jin ◽

J.S. Park ◽

Jong K. Lee ◽

Byeong Hyeon Min ◽

...

Keyword(s):

Volume Fraction ◽

Detailed Examination ◽

Bending Test ◽

High Temperature Strength ◽

Fracture Characterization ◽

Three Point Bending ◽

Vacuum Atmosphere ◽

Additive Materials ◽

Hot Press Process

This study dealt with the characterization of MoSi2 based composites containing three types of additive materials such as SiC, NbSi2 and ZrO2 particles have been investigated, based on the detailed examination of their microstructures and fracture surfaces. The effects of reinforcing materials on the high temperature strength of MoSi2 based composites have been also examined. MoSi2 based composites were fabricated by the hot press process under the vacuum atmosphere. The volume fraction of reinforcing materials in the composite system was fixed as 20 %. The microstructures and the mechanical properties of MoSi2 based composites were investigated by means of SEM, EDS, XRD and three point bending test.

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Effect of Coiling and Normalizing Annealing on the Microstructure of a Newly Developed Cold-Rolled Non-Oriented Electrical Steel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.302.298 ◽

2013 ◽

Vol 302 ◽

pp. 298-303

Author(s):

Yan Ping Zeng ◽

Hui Jie Cui

Keyword(s):

Grain Boundary ◽

Electrical Steel ◽

Volume Fraction ◽

Low Carbon ◽

Coiling Temperature ◽

Pinning Effect ◽

Cold Rolled ◽

Average Size ◽

Hot Rolled ◽

Normalizing Annealing

In order to improve the magnetic properties, copper was added to cold-rolled non-oriented electrical steel with low carbon and low silicon. The grain sizes and precipitates in hot-rolled bands of the investigated steel were quantitatively studied. The results show that the recrystallization of deformed grains has been completed in the coiled bands and the recrystallized grains are fine due to low coiling temperature and pinning effect of precipitates. But grains grew up obviously after normalizing annealing at 850°C for 1h because the mobility of grain boundary is so good at elevated temperature that pinning effect of precipitates can’t prevent the migration of grain boundary. Thus, normalizing annealing is necessary to obtain large grains in hot-rolled band. In addition, the typical morphologies of precipitates in hot-rolled bands are square, rectangular, hexagonal and triangular and they are identified as AlN phase based on EDS and SEAD analysis, which can form by epitaxial growth mode. For the hot-rolled bands coiled at 550°C, the increase of average size and volume fraction of AlN particles with coiling time is mainly related to the growth of AlN particles, whereas for the hot-rolled bands coiled at 650°C, the decrease of average size and the increase of volume fraction of AlN particles with coiling time are chiefly attributed to the precipitation of many small AlN particles. The volume fraction of AlN particles increases with coiling temperature because they precipitate more quickly at 650°C than at 550°C.

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BENDING PROPERTIES OF A FUNCTIONALLY GRADED POLYMERIC COMPOSITE REINFORCED WITH A HYBRID NANOMATERIAL

THE IRAQI JOURNAL FOR MECHANICAL AND MATERIALS ENGINEERING ◽

10.32852/iqjfmme.v21i4.575 ◽

2021 ◽

Vol 21 (4) ◽

pp. 302-319

Author(s):

Mahdi M. S. Shareef ◽

Ahmed Naif Al-Khazraji ◽

Samir Ali Amin

Keyword(s):

Mechanical Properties ◽

Volume Fraction ◽

Functionally Graded ◽

Hybrid Nanocomposites ◽

Bending Test ◽

Fe Model ◽

Al2o3 Nanoparticles ◽

Isotropic Layer ◽

Element Analysis ◽

Three Point Bending

In this paper, functionally graded polymer hybrid nanocomposites have been produced by silica (SiO2) nanoparticles and alumina (Al2O3) nanoparticles distributed in a matrix of epoxy during the ultra-sonication via hand lay-up method. The variation in nanoparticles volume fraction (Vf.) has been given in the thickness direction for reaching the gradation. Each layer has a thickness of 1.2 mm through various concentrations of nanoparticles and is sequentially cast in acrylic moulds to fabricate the graded composite sheet with a 6 mm thickness. To fabricate the functionally graded layers, various concentrations of different nanoparticles (1.5% SiO2, 1% SiO2, epoxy, 2% Al2O3 and 3% Al2O3) have been used for tensile and compressive testing each isotropic layer of functionally graded material (FGM). The mechanical property that was studied for pure epoxy, isotropic and FGM was the flexural resistance. The flexural properties of FGM, isotropic nanocomposite (1% SiO2 + 2% Al2O3) and pristine epoxy, for evaluating their mechanical properties, including flexural stress-strain criteria and flexural Young's modulus, were determined via a Three-point bending test, with loading from the side of silica and alumina for the hybrid-FGM and at one side for the isotropic hybrid nanocomposite and pristine epoxy. The mechanical properties (tensile and compression) and the density of every layer were obtained for the epoxy resin and nanocomposites. They can benefit from the Finite Element Analysis (FEA) of the Three-point bending test via the Design Modeler (ANSYS workbench). The results of experiments were confirmed via building a detailed 3D FE model. Also, the advanced deformation results from the FE model were found in good agreement with the experimental outcomes.

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