Effects of Crystallographic Texture on Internal Stress Superplasticity Induced by Anisotropic Thermal Expansion

1999 ◽  
Vol 601 ◽  
Author(s):  
K. Kitazono ◽  
R. Hirasaka ◽  
E. Sato ◽  
K. Kuribayashi ◽  
T. Motegi
Keyword(s):  
Thermal Expansion ◽  
Thermal Cycling ◽  
Internal Stress ◽  
Crystallographic Texture ◽  
Fiber Texture ◽  
Polycrystalline Materials ◽  
Creep Tests ◽  
Continuum Micromechanics ◽  
Crystallographic Anisotropy ◽  
Polycrystalline Zinc

AbstractPolycrystalline materials having crystallographic anisotropy show internal stress superplasticity under thermal cycling conditions. The deformation mechanism is analyzed using a theoretical model based on continuum micromechanics including the effects of crystallographic texture. The model is experimentally verified through the thermal cycling creep tests using polycrystalline zinc having two kinds of fiber-texture, and agrees well with the experimental results.

scholarly journals Microstructure and Crystallographic Texture of Laser Additive Manufactured Nickel-Based Superalloys with Different Scanning Strategies

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 591
Author(s):  
Xingbo Liu ◽  
Hui Xiao ◽  
Wenjia Xiao ◽  
Lijun Song
Keyword(s):  
Additive Manufacturing ◽  
Epitaxial Growth ◽  
Crystallographic Texture ◽  
Continuous Wave ◽  
Flow Direction ◽  
Fiber Texture ◽  
Laves Phase ◽  
Solidification Structure ◽  
Columnar Grains ◽  
Scanning Strategies

Control of solidification structure and crystallographic texture during metal additive manufacturing is a challenging work which attracts the increasing interest of researchers. In the present work, two kinds of scanning strategies (i.e., single-directional scanning (SDS) and cross-directional scanning (CDS) were used to control the solidification structure and crystallographic texture during quasi-continuous-wave laser additive manufacturing (QCW-LAM) of Inconel 718. The results show that the solidification structure and texture are strongly dependent on scanning strategies. The SDS develops a typical fiber texture with unidirectional columnar grains, whereas the CDS develops a more random texture with a mixture of unidirectional and multidirectional grains. In addition, the SDS promotes the continuously epitaxial growth of columnar dendrites and results in the linearly distributed Laves phase particles, while the CDS leads to the alternately distributed Laves phase particles with chain-like morphology and discrete morphology. The changed stacking features of molten-pool boundary and the switched heat flow direction caused by different scanning strategies plays a crucial role on the epitaxial growth of dendrites and the final solidification structure of the fabricated parts.

Enlarging the Temperature Range for Maximum Wear Resistance of TiNi Alloy Using a NTE Phase

2007 ◽  
Vol 539-543 ◽  
pp. 3261-3266 ◽  
Author(s):  
Iulian Radu ◽  
Dong Yang Li
Keyword(s):  
Wear Resistance ◽  
Thermal Expansion ◽  
Internal Stress ◽  
Frictional Heating ◽  
Negative Thermal Expansion ◽  
High Wear Resistance ◽  
Tini Alloy ◽  
Wear Loss ◽  
Second Phase ◽  
Temperature Range

The near-equiatomic TiNi alloy has been demonstrated to possess high wear resistance, which largely benefits from its pseudoelasticity (PE). However, the PE occurs only in a small temperature range, which makes the wear resistance of this alloy unstable as temperature changes, caused by environmental instability or frictional heating. Therefore, enlarging the working temperature of PE could considerably improve this alloy as a novel wear-resistant material. One possible approach is to develop a self-built temperature-dependent internal stress field by taking the advance of the difference in thermal expansion between the pseudoelastic matrix and a reinforcing phase. Such a T-dependent internal stress could adjust the martensitic transformation temperature to respond changes in environmental temperature so that the temperature range of PE could be enlarged, thus leading to a wide temperature range in which the minimum wear loss is retained. Research was conducted to investigate effects of an added second phase having a negative thermal expansion (NTE) coefficient on the wear resistance of a near-equiatomic TiNi alloy. It was demonstrated that the temperature range of this modified material in which the wear loss dropped was enlarged. In addition, the wear resistance of such a TiNi-matrix composite was on one order of magnitude higher than that of unmodified TiNi alloy.

scholarly journals Tunable giant negative thermal expansion in Ti2O3-based polycrystalline materials

2021 ◽  
Vol 14 (10) ◽  
pp. 107001
Author(s):  
Atsunori Doi ◽  
Satoshi Shimano ◽  
Takuya Matsunaga ◽  
Yoshinori Tokura ◽  
Yasujiro Taguchi
Keyword(s):  
Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Polycrystalline Materials

scholarly journals Irreversible Thermal Expansion of Replicated Aluminium Foam

2018 ◽  
Vol 24 (2) ◽  
pp. 156
Author(s):  
Arkady Finkelstein ◽  
Dmitry Husnullin
Keyword(s):  
Thermal Expansion ◽  
Oxide Film ◽  
Thermal Cycling ◽  
Metal Foam ◽  
Porous Metal ◽  
Extraction Process ◽  
Aluminium Foam ◽  
Expansion Process ◽  
Porous Part

There was found irreversible thermal expansion of large items made of the replicated aluminium foam during the extraction of soluble filler from Al-NaCl composite. Sources of the phenomena were investigated. The expansion is discovered to be caused by incomplete contraction of the porous metal due to oxidation of its internal porous surface during thermal cycling with air and water presence. Significant role of oxide film defects in the expansion process was exposed. There was gained information on dependencies of the irreversible thermal expansion on temperature of the extraction process and metal foam pore size. Measurements of the expansion dynamics showed its finite character. It was also noted that the expansion is limited by the thermal expansion coefficient of used alloy. Finally correction coefficients were obtained that, being applied to nominal sizes of a porous part, compensates the expansion.

Magnetostrictive Fe-Ga Wires with Fiber Texture

2008 ◽  
Vol 1129 ◽  
Author(s):  
Shannon Patrick Farrell ◽  
Patti E. Quigley ◽  
Kyle J. Avery ◽  
Tim D. Hatchard ◽  
Stephanie E Flynn ◽  
...  
Keyword(s):  
Crystallographic Texture ◽  
Low Cost ◽  
Annealing Treatment ◽  
Cost Effective ◽  
Fiber Texture ◽  
Saturation Field ◽  
Energy Harvesters ◽  
Cost Effective Approach ◽  
Wire Method ◽  
Deformation Processes

AbstractRecently, low-cost processing approaches that produce textured thin bodies have engendered interest as cost-effective approaches for fabrication of magnetostrictive Fe-Ga alloys. In particular, wire-forming methods that strictly control the solidification direction could lead to some measure of crystallographic texture control. This is critical for development of large magnetostriction in polycrystals and for use of the alloys in actuators, sensors, energy harvesters and other systems. Magnetostrictive Fe-Ga wires have been prepared using an innovative cost-effective approach – based on the Taylor wire method – that combines rapid solidification and deformation processes. The procedure for making magnetostrictive wires is discussed and the wires are evaluated in terms of microstructure, crystallographic texture and magnetostriction. Results show that the Taylor-based approach is an effective and versatile means to draw 1-3 mm diameter textured Fe-Ga wire. Experimentation on the influence of drawing technique and quench conditions on texture development resulted with production of a strong <100> fiber texture in the Fe-Ga wire. Magnetostriction measurements, in the absence of prestress, indicated a maximum magnetostriction of ˜165 ppm in a saturation field of less than 200 mTesla. This is considered a significant strain for bulk polycrystalline Fe-Ga alloys without a pre-stress or a stress-annealing treatment. The unique properties of wires made with the Taylor-based approach coupled with the low intrinsic cost make this an attractive approach for production of textured magnetostrictive wire for a variety of applications.

scholarly journals The Effects of Reduction and Thermal Treatment on the Recrystallization and Crystallographic Texture Evolution of 5182 Aluminum Alloy

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1380
Author(s):  
Sofia Papadopoulou ◽  
Athina Kontopoulou ◽  
Evangelos Gavalas ◽  
Spyros Papaefthymiou
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Thermal Treatment ◽  
Rolled Product ◽  
Crystallographic Texture ◽  
Texture Evolution ◽  
Fiber Texture ◽  
Electron Back Scatter Diffraction ◽  
Cold Rolled ◽  
Hot Rolled

During forming, thickness reduction and thermal treatment affect the recrystallization and evolution of the crystallographic texture of metallic materials. The present study focuses on the consequences of rolling reduction of a widespread aluminum alloy with numerous automotive, marine and general-purpose applications, namely Al 5182. Emphasis is laid on the crystallographic texture and mechanical properties on both hot and cold-rolled semi-final products. In particular, a 2.8 mm-thick hot-rolled product was examined in the as-received condition, while two cold-rolled sheets, one 1.33 mm and the other 0.214 mm thick, both originating from the 2.8 mm material, were examined in both as-received and annealed (350 °C for 1 h) conditions. Electron back-scatter diffraction indicated the presence of a large percentage of random texture as well as a weak recrystallization texture for the hot-rolled product, whereas in the case of cold rolling the evolution of β-fiber texture was noted. In addition, tensile tests showed that both the anisotropy as well as the mechanical properties of the cold-rolled properties improved after annealing, being comparable to hot-rolled ones.

Predicting Thermal Fatigue Lifetimes for SMT Solder Joints

1992 ◽  
Vol 114 (4) ◽  
pp. 472-476 ◽  
Author(s):  
J. Sauber ◽  
J. Seyyedi
Keyword(s):  
Finite Element ◽  
Solder Joint ◽  
Thermal Cycling ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Finite Element Models ◽  
Creep Tests ◽  
Creep Equation ◽  
Joint Behavior ◽  
Creep Strains

A power-law type creep equation has been added to finite element models to calculate solder joint response to time, temperature, and stress level. The ability of the models to predict solder joint behavior was verified by running a series of creep tests. The models were then solved to determine the solder joint creep strains which occur during thermal cycling. These creep strains were used to predict the degradation of pull strength resulting from thermal cycling. More than 8,600 solder joints were thermally cycled and then individually pull tested to verify the accuracy of the method.

scholarly journals Magnesium Reinforced with Inconel 718 Particles Prepared Ex Situ—Microstructure and Properties

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 798
Author(s):  
Zuzanka Trojanová ◽  
Zdeněk Drozd ◽  
Pavel Lukáč ◽  
Peter Minárik ◽  
Gergely Németh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Internal Friction ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Inconel 718 ◽  
Hot Extrusion ◽  
Fiber Texture ◽  
Ex Situ ◽  
Tension And Compression

Magnesium samples reinforced with 0.7, 1.4, and 2.4 vol.% of Inconel 718 particles were prepared using a disintegrated melt deposition technique followed by hot extrusion. Mechanical properties, thermal expansion, and damping were studied with the aim of revealing the particle influence on the microstructure, texture, tensile and compressive behavior, thermal expansion coefficient, and internal friction. The flow stresses are significantly influenced by the test temperature and the vol.% of particles. A substantial asymmetry in the tensile and compressive properties was observed at lower temperatures. This asymmetry is caused by different deformation mechanisms operating in tension and compression. The fiber texture of extruded composite samples, refined grain sizes, and the increased dislocation density improved the mechanical properties. On the other hand, a decrease in the thermal expansion coefficient and internal friction was observed.

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