bluuebunny/crossref_metadata_2025 huggingface dataset:
The various rising tones in Newcastle English: a phonological distinction?
Authors: Herment Sophie , Leonarduzzi Laetitia , Bouzon Caroline
Published: January 2021

L’anglais de Newcastle est caractérisé par l’utilisation de contours ascendants comme contours par défaut, l’anglais du Tyneside faisant partie en tant que tel des variétés présentant une intonation appelée UNBI (Urban Northern British Intonation), typique des grands centres urbains du Nord de la Grande Bretagne. Une étude précédente sur l’anglais de Newcastle réalisée sur le corpus NECTE a permis de distinguer deux grands types de contours montants : les montées simples ou montées-plateau d’une part, et les montées par paliers, d’autre part. Dans cette étude, nous faisons l’hypothèse que la différence entre ces deux types de contours montants est une distinction phonologique plutôt que phonétique, ce qui signifie que chaque type de montée aurait une fonction spécifique. Nous avons testé cette hypothèse en réalisant une étude pilote basée sur une expérience de perception. Le test ne montre pas de différence phonologique claire entre les deux contours, mais confirme que l’anglais de Newcastle appartient au groupe UNBI. Les résultats du test nous conduisent à une autre hypothèse, à savoir que l’un de nos contours montants serait en fait un contour connu sous le nom de HRT (High Rising Terminal ou Uptalk). HRT a en effet commencé à se diffuser à travers les variétés UNBI, et ce serait le cas à Newcastle, où l’on trouverait une cohabitation entre les deux intonations. Si cela s’avérait exact, on pourrait alors dire qu’il existe bien une distinction phonologique entre les deux types de montées puisqu’il a été démontré que les HRT ont des fonctions interactionnelles.
Linguistic Misogyny as a Parodic Device: Valspeak Markers in Jimmy Fallon’s “Ew!”
Authors: Habasque Pierre
Published: January 2021

Cet article se propose d’étudier la manière dont les marqueurs linguistiques d’un sociolecte perçu comme féminin peuvent être utilisés afin de représenter à la télévision des personnages stéréotypés d’adolescentes. L’analyse porte sur le parler caractéristique de la « Valley Girl, » connu sous le nom de Valspeak, popularisé dans les années 1980 en Californie par le titre éponyme de Frank Zappa, qui parodie ce sociolecte. Le corpus est constitué d’un sketch intitulé « Ew!, » dans l’émission The Tonight Show Starring Jimmy Fallon, qui met en scène le présentateur, sous les traits d’une jeune fille, Sara, et son amie Addison (John Cena). Deux problématiques principales sont soulevées. Il est d’abord suggéré que Fallon a recours à des marqueurs du Valspeak, ainsi qu’à des pratiques linguistiques pouvant être perçues comme féminines, afin de mettre en scène un « parler féminin. » L’analyse porte sur l’utilisation du lexique, de la fréquence fondamentale, d’un contour prosodique (l’intonation montante), d’une qualité de voix (la voix craquée), et de la valeur des voyelles. L’objectif principal du sketch est de faire rire, et l’effet comique est en partie suscité par l’orchestration de la perte de sens du discours des deux personnages. Il est avancé que cette représentation stéréotypée du langage de ces jeunes femmes peut être un cas de « misogynie linguistique, » c’est-à-dire le fait de stigmatiser des pratiques linguistiques perçues (à tort ou à raison) comme féminines.
Stress Ratio Effect on Fatigue Crack Initiation Mechanism of Magnesium Alloy AZ31
Authors: Nakai Yoshikazu , Kikuchi Shoichi , Asayama Kaito , Yoshida Hayata
Published: January 2021

Fatigue tests were conducted under several stress ratios, including negative maximum stress to elucidate the fatigue crack initiation mechanism of a magnesium alloy, AZ31. The specimen surface near the crack initiation site was analyzed by EBSD. On the basis of the results of EBSD analysis, it is concluded for an alternating cyclic stress condition (fully reversed cyclic stress) that fatigue cracks formed from grains where both the grain size and Schmid factor of the basal slip system are large, and that the crack initiation mechanism is based on irreversible slipping and unrelated to twinning. Under compression-compression fatigue test (R=10), cracks were formed along boundary of grains with large Schmid factor and misfit of both side grain are large. At the tip of the initiated crack, twin bands were observed.
Applications of Smart Material of Li2O-(Nb/Ta)2O5-TiO2 Solid Solution Having a Unique Periodical Structure
Authors: Nakano Hiromi
Published: January 2021

In the Li2O-M2O5-TiO2 system, Li1+x-yM1-x-3yTix+4yO3 (M = Nb, or Ta, 0.06 ≤ x ≤ 0.33, 0 ≤ y ≤ 0.175 (LMT) forms a superstructure, known as smart material. The superstructure is formed by periodical insertion of a corundum-type intergrowth layer of [Ti2O3]2+ in a matrix having a trigonal structure during the grain growth. To apply this unique structure as a host material of phosphor, new phosphors doped with Mn4+ ion with a red emission colour, which had a broad peak around 685 nm excited by 493 nm. In order to improve the PL intensity, we investigated the compositions, Mn4+ ratio and crystal structure. Results showed that PL intensity was closely related to Mn4+ ratio and its crystal structure.
Achieving Superplasticity in Fine-Grained Al-Mg-Sc Alloys
Authors: Pereira Pedro H.R. , Huang Yi , Kawasaki Megumi , Langdon Terence G.
Published: January 2021

Superplasticity denotes the ability of a limited number of materials to achieve exceptionally high tensile elongations of at least 400%. Experiments show that the Al-Mg-Sc alloys provide excellent capabilities for achieving superplastic flow and also they can be formed easily in biaxial superplastic forming operations. It is important, therefore, to examine the superplastic flow mechanism when the alloy is prepared using different procedures. This report examines the superplastic characteristics of these alloys after preparation without subjecting to any severe plastic deformation (SPD), after processing using the two SPD procedures of equal-channel angular pressing (ECAP) and high-pressure torsion (HPT) and after processing using the alternative procedure of friction stir processing (FSP). The results are compared using each technique and they are examined with reference to a theoretical model that was developed specifically for superplastic flow in conventional alloys.
Effect of Nano Sodium Titanate Whisker and Aramid Pulp on the Friction and Wear Behavior of Resin-Based Brake Material
Authors: Pei Zhong Zheng , Song Ren Bo , Xu Jie , Feng Yi Fan , Guo Ke
Published: January 2021

The dependence of friction and wear behavior on nanosodium titanate whisker and aramid pulp in a designed resin-based brake material was systematically analyzed. Higher contents of aramid pulp enhanced the hardness of the brake materials. In addition, the maximum impact energy of the material reached 0.392 J/cm2 where the ratio of aramid pulp to sodium titanate whisker is 0.75. At same time, the friction coefficient was stable between 0.38 and 0.45, and the wear rate was 5%. The samples with higher contents of nanosodium titanate whiskers and aramid pulp showed more uniform furrows, fewer delaminated craters, more moderate layers transfer and more stable contact plateaus.
Effect of Extrusion Temperature and Thermal Treatment on Microstructure and Mechanical Properties of Ti-1300 Alloy Tube
Authors: Qi Yun Lian , Zeng Li Ying , Liu Wei , Sun Hua Mei , Du Yu , Xin She Wei , Tan Wei Li , Zhang Si Yuan
Published: January 2021

Effects of extrusion temperature and heat treatment process on the microstructure and mechanical properties of Ti-1300 titanium alloy tube billets were studied by tensile testing and microstructure observation, and the relationship among the thermal processing technique and microscopic structure and mechanical properties of the billets were also investigated. The results showed that the transverse structure of Ti-1300 alloy after extrusion in the a+b two-phase region was uniform and fine. And the longitudinal structure could be seen that the extrusion processing streamline was broken uniformly. Ti-1300 alloy extruded at a+b two-phase has a good match of the strength and ductility, and the ductility of two-phase extrusion is obviously better than that of β single-phase extrusion, especially for the reduction of area.
Microstructure and Mechanical Properties of a Lamellar-Structured Low-Alloy TRIP Steel
Authors: Meng Jiang Ying , Jia Zhi Geng , Wang Tong Liang , Li Kai Fang , Qian Li He
Published: January 2021

In this paper, we report a lamellar-structured low-alloy transformation-induced plasticity (TRIP) steel; the microstructure of the steel consists of alternate lamellae of intercritical ferrite and reverted austenite on microscale, with the latter consisting of bainitic ferrite laths and retained austenite films on nanoscale. Such a microstructure was produced by a heat treatment process similar to that for producing conventional TRIP-assisted steels, i.e. intercritical annealing followed by austempering. Nevertheless, quenched martensite rather than a mixture of ferrite and pearlite was used as the starting structure for intercritical annealing to form austenite, and the resulting austenite was then transformed to bainite by austempering treatment. This steel exhibits much enhanced strength-ductility combinations as compared with those conventional polygonal-structured low-alloy TRIP steels.
Microstructure Evolution during Strain-Induced Transformation of Austenite in an Austempered Ductile Iron (ADI)
Authors: Raghavendran R. , Meena Anil , Amirthalingam Murugaiyan
Published: January 2021

Microstructural evolution during the strain-induced phase transformation of austenite in an Austempered ductile iron (ADI) under various thermomechanical processing conditions is studied in the present study. An alloyed ductile iron is taken as the base material, and thermomechanical treatment is carried out on a Gleeble 3800 thermomechanical simulator coupled with dilatometry. The effect of deformation on the austempering process has been studied by microstructure characterization using optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The variations in retained austenite volume fraction and its carbon content with respect to different austempering times are analyzed to study the effect of strain-induced transformation of austenite. It has been observed that the thermomechanical treatment significantly influences the phase transformation kinetics during the austempering process. The thermomechanical treatment produced a martensite free ausferritic microstructure for all austempering times with a high volume fraction of carbon enriched retained austenite as compared to the conventional heat treatment.
Effects of Alloying Elements on the Stability of ω-Fe Phase in Steel: A Density Functional Theory Study
Authors: Aravindh S. Assa , Pallaspuro Sakari , Cao Wei , Somani Mahesh Chandra , Alatalo Matti , Huttula Marko , Kömi Jukka I.
Published: January 2021

Recent advances in transmission electron microscopy (TEM) in respect of structural characterization down to atomic scale have enabled confirmation of stabilization of long ignored hexagonal omega (ω) phase in steel. The presence of ω phase is suggested to increase the strength of steel, and one of the factors concerning its stabilization is enrichment caused by the presence of certain solute atoms in the nanometer sized areas. Here, we report a density functional theory study conducted on a (3×3×2) ω –Fe supercell by introducing alloying elements in such a way that at a particular instant, either interstitial or substitutional C co-exist with any one of the elements Mn, Cr, Al, Si, and Co in substitutional position. From total energy calculations, we show that the cohesive energy of ω-Fe supercell increases in general, and the most stable combinations in the decreasing order of stability are Csub-Cr > Csub-Co > Csub-Si. Even though the ferromagnetic state is more stable when compared to non-magnetic and antiferromagnetic configurations, the total magnetism of the supercell decreases as some of the atoms acquire negative magnetic moments. The density of states analysis shows that the d-band width of Fe decreases in presence of alloying elements, and this can lead to increased cohesive energy. Our results elucidate that the presence of minor alloying elements can be a factor in stabilizing the metastable ω-phase in steel.
Non-Parametric Comparison of Crystallographic Orientation Distributions
Authors: Schaeben Helmut
Published: January 2021

Revisiting a spiral design for X-ray pole figure measurementsand a symbolic definition of a cumulative crystallographic orientation distributiona one-dimensional deterministic approximately uniform sequential design is appliedto evaluate and cumulate a given orientation density function resulting in a properly definedcumulative crystallographic orientation distribution.It provides a complementary means to compare distributionsin terms of graphs and the Kolomogorov-Smirnov distance.
From Biomaterial to Organoid - Bioprinting for Practice
Authors: Schlegel Volker , Engels Andreas , Stoycheva Vesela , Bifaretti Stefano , Foitzik Andreas H.
Published: January 2021

The current state of technology for 3D printing with biomaterials is based on the extrusion of viscous materials. Mostly, extrusion heads utilize pneumatic pressure systems or stepper motors to force the substrate onto a surface. These methods are well developed for high viscouse materials. However, processing low viscous liquids may cause leakages in the system. This could be solved by applying continuous extrusion. Additionally, in order to process gelable substrates, such as gelatine and agar, tempered print heads in combination with a multi stage tempering system are required to prevent the system from clogging.
The ongoing work presented in this paper focuses on the development of an extrusion system, which should be able to process multiple viscosities of gelatine sequentially. In order to achieve this, several measurements to examine the properties, as well as the material parameters of different biomaterials are performed. In this process gel point, force resistance and elasticity are the factors of particularly interest. Due to their ability to gel and their availability, the most relevant biomaterials are gelatine and agar. Using this data, an extrusion system involving a peristaltic pump, a heated tube and a nozzle, has been developed.
The next step envisaged is to calibrate the extruder based on the obtained data and finally to validate the printing process by printing simple geometric structures. Assuming that a positive evaluation is obtained, the printing system will be tested for printing first organic test structures from patient data using the examined biomaterials.
Magnetization and XRD Studies of Laser Heat Treated SmCo5 Powders
Authors: Seetala Naidu , Henderson Deidre , Jno-Baptiste Jumel , Wen Hao , Guo Sheng Min
Published: January 2021

The microstructure and magnetization of SmCo5 micro-particles may be used as feedstock for 3D printing to make miniature strong magnets. Thus, the magnetic response and microstructures of commercially available SmCo5 micro-particles were studied under various heat treatments using a high wattage laser. The magnetization of laser heat treated powders at 50-watt showed an increase in magnetization, while the 75-watt melt showed a little to no change. Unfortunately, the coercivity of both laser heat treated samples decreased significantly. Oxidation during the heat treatment is suspected to result in low coercivity. Purging with argon-gas prior to laser heating showed improved coercivity. To further minimize the oxidation problem a set of SmCo5 powder was reduced prior to laser heat treatment using a constant flow of hydrogen gas while being heated at various temperatures from 100 oC to 400 oC for a period of ~4 hours. The results show that the magnetization generally increases with the temperature, while the coercivity decreases significantly. Another set of SmCo5 was annealed in a vacuum furnace for one hour at temperatures between 200 oC and 400 oC in order to confirm that no hydride phases were formed during reduction. The magnetization and coercivity showed similar variations with annealing temperature to those for the reduced powders confirming that these variations may be due to change in crystal structure rather than formation of hydrides. X-ray Diffraction (XRD) studies were performed to identify the changes in crystal phases.
Effects of Microstructure on the Hydrogen Embrittlement Resistance of Ultra High Strength Martensitic Steel Sheets
Authors: Shibata Kosuke , Hiramatsu Takuya , Shiraki Atsuhiro , Kinugasa Junichiro , Asai Tatsuya , Utsumi Yukihiro , Murakami Toshio
Published: January 2021

In this study, the relationship between hydrogen embrittlement resistance (HER) and the microstructure of low temperature tempered martensite was investigated using steel sheets which were controlled by carbon content and tempering conditions. Focusing on transition carbides and interstitial carbon content which are peculiar microstructures to low temperature tempered martensite, microstructure was evaluated by synchrotron radiation X-ray diffraction (SR-XRD). The HER was evaluated by U-bending and fracture surface was observed after the slow strain rate test (SSRT). As the result, the HER was improved and fracture morphology was changed from intergranular to quasi-cleavage when the high carbon content and high temperature tempering were adopted. In the steels improved the HER, the increase of the volume fraction of transition carbides and the decrease of interstitial carbon content was confirmed. Hydrogen trapping by the transition carbides could explain the change of the HER and fracture morphology. These results suggested that the hydrogen trapping by the transition carbides was effective to improve the HER of the low temperature tempering martensitic steels.
Hydrogen Embrittlement and Hydrogen Trapping Behaviour in Advanced High Strength Steels
Authors: Smith Ali
Published: January 2021

Modern advanced high strength steels (AHSS) for the automotive sector often contain retained austenite which promotes remarkable combinations of strength and ductility. These high strength steels may however be subject to a risk of hydrogen embrittlement. For the current contribution, hydrogen trapping and embrittlement behaviour were investigated in AHSS compositions having different levels of retained austenite. Hydrogen permeation tests revealed that hydrogen diffusion was slower for increased levels of retained austenite, being controlled most likely by reversible trapping at austenite-matrix interfaces. External hydrogen embrittlement tests via step loading also revealed that resistance to hydrogen was lower for increased levels of retained austenite. It was suggested that during step loading the hydrogen accumulated at austenite-matrix interfaces, leading to cracking when the applied stress was high enough.
Experimental Study and Modelling of the Ferritic Steel Anisotropic Behavior under Associated and Non-Associated Flow Rule
Authors: Soltani Houssem , Chahaoui Oualid , Matougui Nadjoua
Published: January 2021

In the present study, two different yield criteria were investigated to model and compare the yield thresholds functions for the plastic behavior of rolled sheets. These two different yield criteria as described via Hill48 yield quadratic and F. Barlat Yld2000-2d non-quadratic criterion. For this purpose, an experimental device of simple tensile test and the studied material are described. The experimental results in terms of Yield stress and Anisotropic coefficient are estimated from the Associated Flow Rule (AFR) and Non-Associated Flow Rule (NAFR). However, it is found that the criterion of Yld2000-2d is the most appropriate model in comparison with the experimental results.
Titanium Alloy Milling Using Abrasive Water Jet for Repair Application: Modifications in Surface Quality and Material Integrity Following Plain Water Jet Cleaning
Authors: Sourd Xavier , Salem Mehdi , Zitoune Redouane , Hejjaji Akshay , Lamouche Damien
Published: January 2021

Abrasive Water Jet (AWJ) machining has proven to be an effective and versatile technique for milling various kinds of materials, even with low machinability such as aerospace grade titanium alloy Ti6Al4V. Many studies have been performed in order to master this technology and produce geometrically accurate shapes. However, in the context of bonding repairs which require surfaces free from foreign bodies, AWJ machining presents a significant drawback in form of abrasive grit embedment. The goal of this present work is then to investigate the effect of a post-AWJ machining cleaning operation using Plain Water Jet process (PWJ – i.e. without abrasive particles) on the surface quality and material properties. For this, several characterization techniques were employed. It was concluded that the contamination has been reduced by 65% without noticeable changes in depth of cut and crater volume. The AWJ milling operation produced surface and subsurface hardening as well as biaxial compressive residual stress, mostly piloted by the jet pressure. PWJ cleaning reduced the depth of hardening without clear modification in surface hardness.
Development of High-Accuracy Simulation Test Technology for Hot Stamping
Authors: Suzuki Akito , Fujii Yasushi , Kimura Tatsumi , Kawano Masaki , Inazumi Toru
Published: January 2021

A new high temperature testing system was developed to evaluate high temperature deformation behavior in hot stamping process with high accuracy using a hybrid heating system consist of direct resistance heating and high-frequency induction heating. The uniform temperature distribution was achieved in the sheet steel tensile test specimen. The typical hot stamping thermal history was successfully simulated with the combination of the hybrid heating system and the gas cooling system. The strain distribution in high temperature deformation was confirmed to be uniform in the parallel portion of the specimen and the developed testing system may contribute to improving the accuracy in hot stamping CAE analysis.
Microstructure Modification of 3D Printed Aluminium Alloys by Friction Stir Processing
Authors: Du Zheng Lin , Tan Ming Jen , Guo Jun Feng
Published: January 2021

Friction stir processing is a solid-state welding technology capable of joining metal parts without the melting. The microstructure of the material evolved during the process vary from columnar grain along the thermal gradient in the melt pool to fine equiaxed grains. Evaluation on its mechanical properties in terms of micro-hardness was performed. A significant decrease in microhardness was observed in the processed region. The decrease in the microhardness is mainly attributed to the dissolution of hardening precipitates in the aluminium matrix.
Mechanical Property and Heat Treatment Behaviour of Ti-Zr-Fe Alloys
Authors: Chang Ting Hsuan , Adachi Maria , Ueda Masato , Ikeda Masahiko
Published: January 2021

The element of zirconium (Zr) belongs to the same group 4 as Ti in the periodic table. Therefore it possesses similar chemical properties. The Ti-Zr binary system forms a continuous solid solution for both high temperature β phase with the body centered cubic (BCC) structure and low temperature α phase with the hexagonal close-packed (HCP) structure throughout the entire range of composition. As is well known, on the other hand, the element of iron (Fe) is not only inevitable but also effective element in Ti.By incorporating Fe at the stage of alloy design, off-grade sponge titanium can be employed. Both elements seem to be effective in strengthening the titanium alloys. The purpose of this work was to prepare Ti-Zr-Fe alloys and then mechanical property and heat treatment behaviours were investigated as a fundamental research. Ti-x mass% Zr-1mass% Fe alloys (x=0, 5, 10) were melted in a laboratory-scale arc furnace under a high purity argon atmosphere from the sponge Ti, the sponge Zr and the Fe wire. The resulting ingots were hot forged and rolled at approximately 1120 K to obtain plates of approximately 2 mm in thickness. Well-mixed and homogeneous samples could be obtained, oxygen contaminations were less than 0.09 %. Solid solution of Zr into Ti was confirmed by the XRD peak shift in α phase. Vickers hardness and proof stress increased with Zr content. No remarkable changes could be observed in the microstructures after the solution treatment at 1173 K. However, Young’s modulus increased at x=10 by the treatment.
Improvement of Strength and Ductility by Combining Static Recrystallization and Unique Heat Treatment in Co-20Cr-15W-10Ni Alloy for Stent Application
Authors: Ueki Kosuke , Yanagihara Soh , Ueda Kyosuke , Nakai Masaaki , Nakano Takayoshi , Narushima Takayuki
Published: January 2021

The Co-20Cr-15W-10Ni (CCWN, mass%) alloy has excellent corrosion resistance and strength-ductility balance and is applied in almost all balloon-expandable stent platforms. To further reduce the invasiveness of stent placement, it is necessary to reduce the diameter of the stent. That is, both high strength and high ductility should be achieved while maintaining a low yield stress. In our previous studies, it was discovered that low-temperature heat-treatment (LTHT) at 873 K improves the elongation of the CCWN alloy. In this study, we focused on the grain refinement by swaging and static recrystallization to improve the strength of the alloy. The as-swaged alloy was recrystallized at 1373–1473 K for 100–300 s, followed by LTHT. A fine grain structure with an average grain size of 3–17 μm was obtained by static recrystallization. The η-phase (M12X-M6X type precipitates, M: metallic elements, X: C and/or N) formed during the recrystallization at 1373–1448 K. The alloys recrystallized at 1448 and 1473 K had a homogeneous structure with a small variation in the grain size. On the other hand, the alloys recrystallized at 1373 and 1423 K had an inhomogeneous structure in which fine and coarse grains were mixed. Both the strength and ductility of the CCWN alloy were improved by combining high-temperature short-time recrystallization and LTHT.
Integral Computer Model for Simulating Microstructure Evolution during Thermomechanical Processing and Heat Treatment of Steels and Predicting their Final Mechanical Properties
Authors: Vasilyev Alexander A. , Sokolov Dmitry , Sokolov Semen , Kolbasnikov N.G.
Published: January 2021

An integral computer model/program AusEvol Pro was developed to describe the evolution of steel microstructure during thermomechanical processing (hot rolling, forging), as well as subsequent heat treatment (normalization, tempering), and to evaluate the final mechanical properties (yield stress, tensile stress, elongation), hardness and impact toughness. The program implements a set of physically based models that allow quantitative description of all significant processes of steel structure formation with account of the effects of chemical composition both during thermomechanical processing and heat treatment. Calculations of the final mechanical properties are carried out using the developed models that take into account all physically meaningful contributions. The models created are verified both on the extensive database of our own experimental studies and on reliable data from literature for steels of various chemical compositions.
Remelting of Thermal Spraying Coatings - Technologies, Properties and Applications
Authors: Weglowski Marek S. , Dworak Jerzy , Kwiecinski Krzysztof , Pikuła Janusz , Krasnowski Krzysztof , Jachym Robert , Dymek Stanisław , Kalemba-Rec Izabela , Wrona Adriana , Kustra Katarzyna
Published: January 2021

The most popular spraying technologies include: flame spraying, arc spraying and plasma spraying. Spraying technologies allow for the formation of coatings with a desired chemical composition and thickness. However, such coatings characterize by numerous imperfections associated with the nature of the process itself. It is obvious that some of imperfections in thermal spraying coatings can be eliminated by choosing the right parameters of the process. However, in order to improve the properties and eliminate material discontinuous, it is necessary to conduct the remelting process. Research in most cases, showed that the reduction of porosity and simultaneous increase in hardness are possible only by remelting the coating using different heat sources. By adjusting the technological parameters and remelting speed, it is possible to precisely control the depth of the remelted material and thus the properties of final coatings. The paper presents the remelting processes of thermal spraying coatings in relation to technologies, properties and applications.
Processing of Nanostructured Bulk Fe-Cr Alloys by Severe Plastic Deformation
Authors: Weissitsch Lukas , Stückler Martin , Wurster Stefan , Pippan Richard , Bachmaier Andrea
Published: January 2021

The processing of binary alloys consisting of ferromagnetic Fe and antiferromagnetic Cr by severe plastic deformation (SPD) with different chemical compositions has been investigated. Although the phase diagram exhibits a large gap in the thermodynamical equilibrium at lower temperatures, it is shown that techniques based on SPD help to overcome common processing limits. Different processing routes including initial ball milling (BM) and arc melting (AM) and a concatenation with annealing treatments prior to high-pressure torsion (HPT) deformation are compared in this work. Investigation of the deformed microstructures by electron microscopy and synchrotron X-ray diffraction reveal homogeneous, nanocrystalline microstructures for HPT deformed AM alloys. HPT deformation of powder blends and BM powders leads to an exorbitant increase in hardness or an unusual fast formation of a σ-phase and therefore impede successful processing.
Influence of Substitution of Fe by Mo on Heat Treatment Behavior in Ti-Mo-Fe Alloys
Authors: Mizuta Kyosuke , Miyake Shotaro , Ikeda Masahiko , Ueda Masato
Published: January 2021

In order to reduce the cost of β-type Ti alloys, the use of Fe as an alloying element has been studied. However, Fe is known to have a very high diffusion coefficient in β-Ti of about 2.6×10-12 m2/s at 1200 K, and its behavior during heat treatment is expected to be difficult to control. By contrast, Mo, which is also a β-stabilizing element, has a diffusion coefficient of only about 2.5×10-14 m2/s at 1200 K, i.e., roughly 100 times smaller than that of Fe1), 2). In this study, the effect of the partial substitution of Fe with Mo on the aging behavior of β-Ti alloys was investigated using X-ray diffraction, electric resistivity, and Vickers hardness measurements. Ti-Mo-Fe alloys were solution-treated by holding at 1173 K for 3.6 ks and then quenching in ice water. In the X-ray diffraction patterns for the resulting samples, only peaks associated with the β phase were identified. It was found that the electrical resistivity and Vickers hardness decreased with increasing Mo content. As the Mo-to-Fe ratio increased, the decrease in electrical resistivity and the increase in Vickers hardness occurred later during the isothermal aging process. This was due to a delay in isothermal ω-phase precipitation.
Goss Texture Evolution in a Grain-Oriented Fe-6.5wt%Si Steel Processed by Strip-Casting
Authors: Liu Xiang , Xu Hai Jie , Gao Zhen Yu , Xu Yun Bo , Yu Jing , Jiao Hai Tao , Li Yuan Hua , Li Jian Ping
Published: January 2021

Fe-6.5wt%Si steel is an excellent soft magnetic material due to the near-zero magnetostriction and low core losses. In this study, a 0.3 mm-thick grain-oriented 6.5wt%Si steel sheet was produced by a novel strip casting and two-stage rolling. The microstructure and texture evolution were investigated with a special emphasis on the nucleation and growth of Goss grains. The thin normalized strip was composed of large columnar grains and small equiaxed grains. During intermediate annealing, Goss grains nucleated in the shear bands of the deformed <111>//ND grains, and the deformed {111}<112> grains provided most of the nucleation sites. After primary annealing, the Goss grains distributed across the entire thickness, which was different from the conventional rolling route. The fraction of high-angle boundaries (20°-45°) surrounding the Goss grains was apparently higher than those of the matrix grains, which promoted the abnormal growth of the Goss grains during secondary recrystallization.
The Effect of Aging Conditions on the Stress Relaxation Behavior of 17-7PH Stainless Steel
Authors: Yamasaki Shota , Takano K.
Published: January 2021

17-7PH stainless steel is high age-hardening property due to precipitate NiAl intermetallics by aging heat treatment after the deformation induced martensitic transformation by cold working. In this study, the effect of aging conditions on stress relaxation behavior of 17-7PH stainless steel was investigated, and the mechanism of the stress relaxation was discussed. The 0.2% proof stress after aging at 753K for 180s-18ks is about 450MPa, and then decreases after 18ks. On the other hand, the stress relaxation ratio decreases by long time aging at 753K. The dislocation density of 17-7PH decreases by long time aging at 753K. The formation of NiAl clusters around 5nm by 3D-AP analysis is observed in 17-7PH aged at 753K for 1.8ks. It is suggested that the reduction of the stress relaxation ratio after long time aging at 753K is caused by NiAl clusters and decreasing mobile dislocation density.
Development of Cu Coating on Ceramic Substrates by Low Pressure Cold Spray and its Deposition Mechanism Analysis
Authors: Yu Minjae , Ichikawa Yuji , Ogawa Kazuhiro
Published: January 2021

Cold spray (CS) is a solid-state deposition technique of micron-sized metallic powder in an ultra-high velocity gas using a de Laval nozzle. CS is a unique deposition technique due to its use of relatively lower gas temperatures in comparison to other thermal processes. Consequently, high-temperature oxidation and phase transformations of deposited powders are largely restricted while the operating cost of CS is much lower than that of other thermal processes. Generally, the low pressure cold spray (LPCS) technique is used for the deposition of metallic powders on metallic substrates, while only a few studies of metallic particle deposition on ceramic substrates have been conducted, and it was found that the deposition of metallic powders on ceramic substrates was quite difficult. In this study, improved LPCS deposition of copper coatings on zirconia substrates was investigated. It is known that deposition of a metallic powder on a ceramic substrate is difficult due to the differences in material bonding and several properties of the two materials. These difficulties in LPCS deposition were solved using three different approaches, namely 1) use of copper and aluminum composite powders and 2) laser pre-treatment and 3) laser texturing of zirconia substrates. It was found that pure copper powder coatings on the as-received and various treated substrates were delaminated in the interface as expected. However, the deposition was improved for all substrates by using the copper and aluminum composite powder. While the laser pre-treated substrate was not effective for the deposition of the copper and aluminum composite powder, thick coatings were obtained for the deposition on the laser pre-treated with heat treatment substrate and the laser-textured substrate.
Dislocations of Ti-600 Alloy Crept at 600°C with Two Stresses
Authors: Zeng Li Ying , Mao Xiao Nan , Hong Quan , Qi Yun Lian , Zhao Yong Qing
Published: January 2021

Microstructure and dislocations were observed for Ti-600 alloy crept at the temperature of 600°C with the stress of 200MPa and 300 MPa. The results indicate that more precipitation phases could be found both in β phases and at phase boundaries for the alloy after creep tests, and the width of the phase boundary become broader obviously. Also more dislocations could be seen at or around the precipitation phases for the alloy crept at 600°Cwith the stress of 200MPa. Dislocation density is rather big in some regions, dislocations aggregate in precipitation phases, phase boundaries and sub-grain boundaries. Some tangled dislocations or regular arranged dislocations could also be found around precipitation phases. Condensed three-dimensional dislocation meshes could be found in the alloy crept for the alloy crept at 600°Cwith two stresses. For the alloy crept at 600°Cwith the stress of 200MPa, faults originated from boundaries of α lamellar could be found in α lamellar. Some of these faults extend to boundaries of α lamellar, and some stop or end off in α lamellar. While for the alloy crept at 600°Cwith the stress of 300MPa, dislocation tend to arrange in dislocation walls, form bamboo-like structure along the direction of α lamellar, which would expand and penetrate the whole grain of elongated dislocation walls, and at last stop at grain boundaries.
Microstructure and Mechanical Properties of Cu-Fe Alloys via Powder Metallurgy
Authors: Zhang Chen Zeng , Chen Cun Guang , Lu Tian Xing , Li Pei , Yang Fang , Wang Wen Wen , Guo Zhi Meng
Published: January 2021

Copper Ferro Alloys (CFAs) have an excellent shielding effect in the electromagnetic field, as well as the similar good conductivity and ductility with copper, and strong magnetism and toughness as analogous to iron. Consequently, it is considered to be novel structural and functional materials with huge development potential and wide application foreground. The influence of the content, size and distribution of Fe phase in the Cu matrix on the electromagnetic shielding property of CFAs is crucial. In the present study, CFAs with various Fe content were fabricated via powder metallurgy (P/M) combining with deformation processing. The microstructure, electrical conductivity, magnetic and mechanical properties of CFAs were investigated by optical microscopy (OM), scanning electron microscopy (SEM), X-Ray diffraction (XRD), and tensile test. The results indicated that P/M CFAs with the homogenous and fine in-situ Fe particles showed better comprehensive performance compared to those prepared by conventional casting. Based on the microstructure observation, mechanical properties were discussed.
Metallic Composites, Prepared by Deformation Processing
Authors: Korznikova Galia F. , Zhilyaev Alexander P. , Sarkeeva Aygul A. , Lutfullin Ramil Ya. , Shayahmetov Ruslan U. , Khalikova Gulnara R. , Khisamov Rinat Kh. , Nazarov Konstantin S. , Mulyukov Radik
Published: January 2021

The main point of successful manufacture of metallic composites by direct bonding of dissimilar materials is achieving a homogeneous interface bonding. Two different types of deformation techniques for fabrication of metal composites were investigated. The first one was developed on the basis of high pressure torsion associated with a high energy impact on the material where part of energy involved can be dissipated via non equilibrium phase transition realization. This deformation due to high shear deformations allows not only to form a nanostructure, but also to bond dissimilar metals. Moreover, this method allows for a relatively short time and in a number of compounds to receive in one step at room temperature monolithic composites of sufficient size to certify the structure and properties. The second technique is diffusion bonding which integrate one material with the other by pressure under high temperature. In order to clarify the bonding mechanism by plastic deformation of dissimilar materials, the microstructural and some mechanical properties were studied in the processed samples.
Unmixed Joint of A1050 and C1020 by Friction Stir Butt Welding
Authors: Nagaoka Toru , Kyouda Takeshi , Tongge Shao , Zhang Hua
Published: January 2021

Friction stir butt welding of C1020 and A1050 were carried out. To avoid the deterioration of strength and workability of the joints, dispersion of copper fragments into aluminum was suppressed. The effect of tool tilt angle on root flaw at the bottom part was investigated. To obtain unmixed joints, the probe was plunged into only aluminum. Under the condition of tool tilt angle of 0°, equiaxed grains were observed at the bottom of A1050 near the bonding interface. It indicates that material flow and heat input could promote the reaction of copper and aluminum at the bottom part. In contrast, under the condition of tool tilt angle of 3°, unbonded area remained at the bonding interface at the bottom. The lack of penetration near the bonding interface was larger than that of tool tilt angle of 0°.
Suppression of Intergranular Fracture in 7000 Series Aluminum Alloys
Authors: Itoh Goroh , Hiyama Keisuke , Lyu Bo Fan , Kobayashi Junya
Published: January 2021

The 7000 series aluminum alloys suffer from intergranular fracture (IGF) that limits the use of the alloys, although they have highest strength among aluminum alloys. The types of IGF can be classified into two categories: (i) with smooth fracture surface showing practically no plastic deformation that takes place in hydrogen embrittlement and stress corrosion cracking, and (ii) with shallow and fine dimples on the fracture surface showing localized plastic deformation inside precipitate free zones. In this study, attempts have been made to suppress the IGF of both types by (a) controlling precipitate microstructure on grain boundaries by quench control and (b) controlling grain boundary morphology by strain induced boundary migration. The IGF of type (i) (hydrogen embrittlement) was successfully suppressed both by the two controlling processes.
Characteristics of Cube Orientation for Pure Iron Tape Fabricated by Cold Rolling and Annealing
Authors: Okai Daisuke , Yamamoto Atsushi , Doi Toshiya , Adachi Hiroki
Published: January 2021

A pure iron tape with cube orientation was fabricated by cold rolling and annealing. The orientation characteristics of the pure iron tape were evaluated using electron back-scattering diffraction (EBSD) analysis. The secondary recrystallized grains with cube orientation was formed on the tape surface for the pure iron tape. The coarse grains with a grain size of ca. 1mm were observed on the tape surface. The areal fraction of cube orientations with an angular deviation ≤ 20 ̊ amounts to ca. 81%.
Effects of Nb Content and Heat Treatment on Fretting Wear Behavior of Ti-Nb Alloys
Authors: Nishimura Naoki , Miura-Fujiwara Eri , Yamasaki Tohru
Published: January 2021

Ti-Nb alloys in deionized water and Hanks' balanced salt solution were investigated at 310K using a ball-on-disc type frictional test machine with a ZrO2 ball counterface. In this study, besides the fretting wear behavior of Ti-Nb alloys was investigated, the relationship between the microstructure and mechanical properties of the Nb-added Ti alloy was investigated, and the relationship between the composition and hardness on the fretting wear of the alloy will be clarified from the results of the wear volume and surface analysis of wear track. The results obtained from the frictional test indicate that the dynamic coefficient of friction converged to a constant value with time variation. Also, wear volume in HBSS was smaller than in water, and wear volume of heat-treated became smaller than As-Rolled. Microstructural observations suggest the scars of adhesive wear were observed. Comparing each morphology, the ratio of the peeling part was more significant in Ti-Nb alloys, which have α+β than in Ti-Nb alloys, which have only β. Moreover, the results of Open circuit potentiometry indicate that the corrosion potential difference increased with wear. This is most likely due to the passive film was damaged. Besides, the corrosion potential difference of β-Ti-Nb alloy heat-treated with HBSS is small. It is assumed that there is an influence of HBSS besides the fine structure.
Modelling Dilatometry Data of Isothermal ω-Phase Formation in a Strongly β-Stabilised TiV-Alloy
Authors: Enzinger Robert Josef , Luckabauer Martin , Ichitsubo Tetsu , Würschum R.
Published: January 2021

In the most relevant technical β-titanium alloys, the extensive formation of the metastable ω-phase during common heat treatments has been a long-standing problem due to the deteriorating effect of this phase on the material properties. By means of dilatometry, the formation of the isothermal ω-phase has been investigated during ageing a Ti-21at.-%V-sample at 300 °C. A model has been developed, which allows to quantitatively correlate the maximum length changes appearing upon ageing to changes occurring at the microscopic scale, i.e. variations of the lattice constants, phase fractions and concentrations of vanadium in the phases appearing. The length change predicted by the model is in very good accordance with the data measured paving the way for further kinetic discussion and ultimately for deriving kinetic parameters.
Ultrasonic Processing of Magnesium Alloy for Property Enhancement
Authors: Emadi Payam , Vandersluis Eli , Andilab Bernoulli , Rinaldi Michael , Ravindran Comondore
Published: January 2021

The reduction of harmful greenhouse gas (GHG) emissions can be realized by utilizing lightweight structural metals, such as magnesium. Magnesium alloys have the potential to replace higher-density aluminum and ferrous components in automotive and aerospace industries, thereby decreasing vehicle weight and the associated fuel requirements. However, their strength and ductility must be improved to ensure widespread application. This goal can be achieved through ultrasonic processing in the molten state, a technique that is gaining popularity in the manufacturing of light alloys. In this study, the effects of high-intensity ultrasonic vibration on the microstructure and hardness of AZ91E Mg alloy was investigated. The molten alloys were subjected to sonication of varying durations, and the resulting castings were characterized using optical microscopy, scanning electron microscopy and hardness testing. Sonication was found to successfully increase the hardness of the alloy relative to the base condition. This improvement was attributed to the refinement of the magnesium grain structure as well as the Mg17Al12 and Mn-Al secondary phases in the sonicated alloys. The competitiveness of magnesium alloys can be significantly enhanced via ultrasonic processing, offering important opportunities for the production of greener, light metal components.
Computer Prediction of Phase Fraction in Multipass Weld of Duplex Stainless Steel - Proposal of Microstructural Improvement Welding Process -
Authors: Saida Kazuyoshi , Ogura Tomo , Yamashita Shotaro , Oikawa Yusuke
Published: January 2021

Computer simulation of the α/γ phase transformation in multipass weld of duplex stainless steel was made for predicting the distribution of the γ phase fraction in the weld metal (WM) and HAZ. The kinetic equations including rate constants of the dissolution behaviour as well as precipitation behaviour of γ phase were determined by isothermal heat treatment test. Based on the kinetic equations determined, the distribution of the γ phase fraction in multipass weld of duplex stainless steel was calculated applying the incremental method combined with the heat conduction analysis in welding process. The γ phase fraction was reduced in the higher temperature HAZ and WM, however, that in the reheated HAZ and WM was increased and recovered to the base metal level. Microstructural analysis revealed that the calculated results of the γ phase fraction in multipass weld were consistent with experimental ones. Based on the computer prediction, the microstructural improvement welding (“reheat bead welding”) process, with analogous concept to the temper bead welding technique, was newly proposed for recovering the γ phase fraction in weld even in the as-welded situation.