scholarly journals Effect of Process Parameters and Definition of Favorable Conditions in Multi-Material Extrusion of Bimetallic AZ31B–Ti6Al4V Billets

2020 ◽  
Vol 10 (22) ◽  
pp. 8048
Author(s):  
Daniel Fernández ◽  
Alvaro Rodríguez-Prieto ◽  
Ana María Camacho

This paper investigates the extrusion process to manufacture bimetallic cylinders combining a magnesium alloy core (AZ31B) and a titanium alloy sleeve (Ti6Al4V) of interest in aeronautical applications. A robust finite element model has been developed to determine the most influential parameters and to study the effect of them on the extrusion force and damage induced by means of Design of Experiments (DOE) and Taguchi method. The results show that the most influential parameters in the extrusion forces are the friction between sleeve and container/die and the height of the cylinder; and the less influential ones are the process temperature and ram speed. Moreover, minimum values of forces along with low damage can be reached by favorable interface contact conditions, minimizing the friction at the core-container/die interface, as the main influencing factor; followed by the geometrical dimensions of the billet, being the billet height more important when paying attention to the minimum forces, and being the core diameter when considering the minimum damage as the most important criterion. The results can potentially be used to improve the efficiency of this kind of extrusion process and the quality of the extruded part that, along with the use of lightweight materials, can contribute to sustainable production approaches.

2009 ◽  
Vol 83-86 ◽  
pp. 157-164 ◽  
Author(s):  
Chao Yang Sun ◽  
Qing Dong Zhang

Superalloy IN718 large tube is used in critical jet engine applications, while manufacturing such components, the control of temperature during tube hot extrusion is of paramount importance. To determine the relation between technological factors and the temperature rise, extrusion force during tube hot extrusion of superalloy IN718, a numerical model was developed to for the large tube hot extrusion through die and over mandrel. The constitutive behaviour of the material and friction at the extrusion temperatures are established as a thermoplastic process. In order to investigate the influence of technological parameters of extrusion process on the temperatures rise and extrusion force, then the extrusion variables such as friction factor, ram speed, tool and billet preheating temperature are taking into consideration. Besides tool preheating temperature, other parameters have a great influence on temperature rise of billet during the extrusion process. All of technological parameter of study in this paper have a significant influence on the extrusion force. Moreover, based on the simulation results, the case with tool preheating temperature of 300°C should avoid during the technology making.


2021 ◽  
Vol 13 (2) ◽  
pp. 63-75
Author(s):  
Anupama Francy Kothasiri ◽  
◽  
Srinivasa Rao Chalamalasetti ◽  
Gopalakrishnaiah Peteti ◽  
◽  
...  

Extrusion is a simple metal forming process in which a block of metal is forced through a die orifice with a certain shape under high pressure. This extrusion process is influenced by many process parameters such as die angle (DA), ram speed (RS), coefficient of friction (COF), Extrusion ratio, Die land height, work piece diameter and length, material properties etc. In extrusion process, extrusion force is crucial parameter, the flow of metal and hence the extrusion force is significantly influenced by the above parameters which results in quality of the product. The present study numerically investigates the influence of major process parameters such as die angle, ram speed, coefficient of friction on the extrusion process. The AA2024 material is chosen as work piece material and the extrusion force and damage is considered as the output responses. The input process parameters are varied in three levels (Level - 1: 10° DA, 1.6mm/min RS, 0.06 COF; Level - 2: 20° DA, 3.2mm/min RS, 0.08 COF; Level - 3: 30° DA, 4.8mm/min RS, 0.01 COF). Numerical simulations are performed by using DEFORM 3D software. The simulations are conducted as per L27 orthogonal array. From the results it is observed that Increase of die angle, ram speed and coefficient of friction increases the extrusion force. The die angle has highest (86.45%) influence on the extrusion force, then after ram speed (6.60%). The coefficient of friction has insignificant influence (0.55%). It is also noticed that the damage is considerable after the 20° die angle. A multi parameter optimization is also done by using the Grey relation analysis by considering the equal weightage of extrusion force and damage. The optimum levels of input process parameters for the minimum extrusion force and damage is DA level 1, RS level 1, and COF level 3.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7568
Author(s):  
Daniel Fernández ◽  
Alvaro Rodríguez-Prieto ◽  
Ana María Camacho

This paper investigates the effect that the selection of the die material generates on the extrusion process of bimetallic cylindrical billets combining a magnesium alloy core (AZ31B) and a titanium alloy sleeve (Ti6Al4V) of interest in aeronautical applications. A robust finite element model is developed to analyze the variation in the extrusion force, damage distribution, and wear using different die materials. The results show that die material is a key factor to be taken into account in multi-material extrusion processes. The die material selection can cause variations in the extrusion force from 8% up to 15%, changing the effect of the extrusion parameters, for example, optimum die semi-angle. Damage distribution in the extrudate is also affected by die material, mainly in the core. Lastly, die wear is the most affected parameter due to the different hardness of the materials, as well as due to the variations in the normal pressure and sliding velocity, finding critical values in the friction coefficient for which the die cannot be used for more than one forming stage because of the heavy wear suffered. These results can potentially be used to improve the efficiency of this kind of extrusion process and the quality of the extruded part that, along with the use of lightweight materials, can contribute to sustainable production approaches.


2016 ◽  
Vol 6 (2) ◽  
Author(s):  
Rosa Jaitin

This article covers several stages of the work of Pichon-Rivière. In the 1950s he introduced the hypothesis of "the link as a four way relationship" (of reciprocal love and hate) between the baby and the mother. Clinical work with psychosis and psychosomatic disorders prompted him to examine how mental illness arises; its areas of expression, the degree of symbolisation, and the different fields of clinical observation. From the 1960s onwards, his experience with groups and families led him to explore a second path leading to "the voices of the link"—the voice of the internal family sub-group, and the place of the social and cultural voice where the link develops. This brought him to the definition of the link as a "bi-corporal and tri-personal structure". The author brings together the different levels of the analysis of the link, using as a clinical example the process of a psychoanalytic couple therapy with second generation descendants of a genocide within the limits of the transferential and countertransferential field. Body language (the core of the transgenerational link) and the couple's absences and presence during sessions create a rhythm that gives rise to an illusion, ultimately transforming the intersubjective link between the partners in the couple and with the analyst.


2020 ◽  
Vol 65 (10) ◽  
pp. 904
Author(s):  
V. O. Zamorskyi ◽  
Ya. M. Lytvynenko ◽  
A. M. Pogorily ◽  
A. I. Tovstolytkin ◽  
S. O. Solopan ◽  
...  

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The results of magnetic research showed that the coating of magnetic nanoparticles with a shell gives rise to the appearance of two simultaneous effects: the modification of the core/shell interface parameters and the parameter change in both the nanoparticle’s core and shell themselves. As a result, the core/shell particles acquire new characteristics that are inherent neither to Fe3O4 nor to CoFe2O4. The obtained results open the way to the optimization and adaptation of the parameters of the core/shell spinel-ferrite-based nanoparticles for their application in various technological and biomedical domains.


2018 ◽  
Author(s):  
Olga Dorofeeva ◽  
Любовь Викторовна Чернова

Обращаясь к рассмотрению вопроса о доминантно-функциональной структуреидиостиля, авторы раскрывают дефиницию «идиостиль» в его связи с экстра- и интралингвистическими факторами. Рассматривая творчество публициста М.Ф. Дороновича через призму одножанровых текстов, авторы выделяют доминанты, составляющие ядро идиостиля публициста. К числу таковых относятся оценочная метафоричность, гиперболичность, фразеологичность, реализующиеся как на уровне тропов, так и на уровне синтаксических фигур.Addressing the issue of dominant-functional structure of idiostyle, the authors reveal the definition of "idiostyle" in its connection with extra- and intralinguistic factors. Considering the creativity of the writer M.F. Doronovich through the lens of various genres of texts, the authors identify the dominant components of the core of the idiostyle of the writer. These include evaluative metaphoricity, hyperbolicity, phraseology, which are implemented both at the level of tropes and at the level of syntactic figures.СВЕДЕНИЯ О ГРАНТАХ И ФИНАНСИРОВАНИИИсследование подготовлено при поддержке Российского фонда фундаментальных исследований (отделение гуманитарных и общественных наук) и Министерства образования, науки и молодёжной политики Краснодарского края в рамках научного проекта № 18-412-230008 а(р) «Язык и стиль публикаций М.Ф. Дороновича в кубанских дореволюционных газетах». Руководитель проекта – О.А. Дорофеева.


2018 ◽  
Author(s):  
Cody Fullerton

For years, the gold-standard in academic publishing has been the peer-review process, and for the most part, peer-review remains a safeguard to authors publishing intentionally biased, misleading, and inaccurate information. Its purpose is to hold researchers accountable to the publishing standards of that field, including proper methodology, accurate literature reviews, etc. This presentation will establish the core tenants of peer-review, discuss if certain types of publications should be able to qualify as such, offer possible solutions, and discuss how this affects a librarian's reference interactions.


Author(s):  
Mark Oprenko

The definition of the multimorbidity concept reveals insufficient specificity of the comorbidity and multimorbidity definitions and, as a result, confusion in the use of these terms. Most authors are unanimous that the “core” of multimorbidity is presence of more than one disease in a patient. These coexisting diseases can be pathogenetically interconnected and non-interconnected. Regardless, the degree of multimorbidity always affects prognosis and quality of life.


Author(s):  
E. M. Ratnikov ◽  
D. O. Milko

Annotation Purpose. Development of a program and methods for conducting experimental studies of the extrusion process with the definition of parameters and modes of operation of the extruder to improve its energy performance. Methods. Methods of mathematical statistics, synthesis, analysis, description and modeling were used. Results. The application of mathematical methods, in particular mathematical planning, reduces the number of experiments several times, and allows to evaluate the role of influencing factors, obtain a mathematical model of the process and determine the optimal conditions for its parameters and modes, etc. Conclusions. The methodology for experimental studies of a screw extruder is presented with the necessary equipment and methodology for processing the obtained experimental data. A mathematical method of planning, which reduces the number of experiments several times, allows us to evaluate the role of factors affecting productivity and energy intensity is presented. Keywords: extruder, auger, nutrients, research methodology, extrusion, processing, feed.


Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 420
Author(s):  
Ang Deng ◽  
Wonkeun Chang

We numerically investigate the effect of scaling two key structural parameters in antiresonant hollow-core fibers—dielectric wall thickness of the cladding elements and core size—in view of low-loss mid-infrared beam delivery. We demonstrate that there exists an additional resonance-like loss peak in the long-wavelength limit of the first transmission band in antiresonant hollow-core fibers. We also find that the confinement loss in tubular-type hollow-core fibers depends strongly on the core size, where the degree of the dependence varies with the cladding tube size. The loss scales with the core diameter to the power of approximately −5.4 for commonly used tubular-type hollow-core fiber designs.


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