scholarly journals Mechanical Properties and Corrosion Characteristics of Thermally Aged Alloy 22

2002 ◽  
Author(s):  
Rau´l B. Rebak ◽  
Paul Crook
Keyword(s):  
Corrosion Resistance ◽  
Laboratory Data ◽  
Aged Alloy ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
Secondary Phases ◽  
Waste Container ◽  
Alloy 22 ◽  
High Level ◽  
The Impact

Alloy 22 (UNS N06022) is a candidate material for the external wall of the high-level nuclear waste containers for the potential repository site at Yucca Mountain. In the mill-annealed (MA) condition, Alloy 22 is a single face centered cubic phase. When exposed to temperatures on the order of 600°C and above for times higher than 1 h, this alloy may develop secondary phases that reduce its mechanical toughness and corrosion resistance. The objective of this work was to age Alloy 22 at temperatures between 482°C and 760°C for times between 0.25 h and 6,000 h and to study the mechanical and corrosion performance of the resulting material. Aging was carried out using wrought specimens as well as gas tungsten arc welded (GTAW) specimens. Mechanical and corrosion testing was carried out using ASTM standards. Results show that the higher the aging temperature and the longer the aging time, the lower the impact toughness of the aged material and the lower its corrosion resistance. However, extrapolating both mechanical and corrosion laboratory data predicts that Alloy 22 will remain corrosion resistant and mechanically robust tbr the projected lifetime of the waste container.

scholarly journals Influence of Ti Addition on the Strengthening and Toughening Effect in CoCrFeNiTix Multi Principal Element Alloys

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1511
Author(s):  
Dukhyun Chung ◽  
Heounjun Kwon ◽  
Chika Eze ◽  
Woochul Kim ◽  
Youngsang Na
Keyword(s):  
Fracture Toughness ◽  
High Fracture Toughness ◽  
Molar Ratio ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
Secondary Phases ◽  
High Fracture ◽  
Principal Element ◽  
Multi Phase ◽  
Ti Addition

Multi principal element alloys have attracted interests as a promising way to balance the bottleneck of the “inverse relationship” between high hardness and high fracture toughness. In the present study, the authors demonstrate the effects of Ti addition on the microstructures and mechanical properties of the CoCrFeNiTix alloys (x values in molar ratio, x = 0.7, 1.0, and 1.2), which exhibits a multi-phase structure containing face-centered cubic phase and various secondary phases, such as sigma, Laves, and (Cr,Fe)-rich phase. Throughout the combined experimental examination and modeling, we show that superb hardness (~9.3 GPa) and excellent compressive strength (~2.4 GPa) in our alloy system are attributed to solid-solution strengthening of the matrix and the formation of hard secondary phases. In addition, high indentation fracture toughness is also derived from the toughening mechanism interplay within the multiple-phase microstructure. At the fundamental level, the results suggest that multi-principal element alloys containing dual or multi-phase structures may provide a solution for developing structural alloys with enhanced strength-toughness synergy.

Corrosion Processes Affecting the Performance of Alloy 22 as a High-Level Radioactive Waste Container Material

2000 ◽  
Vol 663 ◽  
Author(s):  
G.A. Cragnolino ◽  
D.S. Dunn ◽  
Y.-M. Pan ◽  
O. Pensado
Keyword(s):  
Radioactive Waste ◽  
Electrochemical Techniques ◽  
Department Of Energy ◽  
Localized Corrosion ◽  
Dissolution Behavior ◽  
Uniform Corrosion ◽  
High Level Radioactive Waste ◽  
Waste Container ◽  
Alloy 22 ◽  
High Level

ABSTRACTAlloy 22 is the material preferred by the U.S. Department of Energy for the waste package outer container for geological disposal of high-level radioactive waste at the proposed site in Yucca Mountain, Nevada. Alloy 22 is considered to be extremely resistant to various modes of aqueous corrosion over broad ranges of temperature, pH, and concentration of anionic and oxidizing species. Uniform corrosion under passive dissolution conditions, localized corrosion in the form of crevice corrosion, and stress corrosion cracking are discussed on the basis of experimental results obtained with mill annealed, thermally treated, and welded specimens using electrochemical techniques. The approach developed for long-term performance prediction, including the use of empirically derived parameters for assessing localized corrosion and the modeling of the passive dissolution behavior, is described.

scholarly journals Characterization of the Resistance of Alloy 22 to Stress Corrosion Cracking

2002 ◽  
Author(s):  
Kenneth J. King ◽  
John C. Estill ◽  
Rau´l B. Rebak
Keyword(s):  
Slow Strain Rate Test ◽  
Environmentally Assisted Cracking ◽  
Waste Container ◽  
Alloy 22 ◽  
Aqueous Environments ◽  
Current Design ◽  
Rate Test ◽  
High Level Nuclear Waste ◽  
High Level

In its current design, the high-level nuclear waste container includes an external layer of Alloy 22 (Ni-22Cr-13Mo-3W-3Fe). Since the containers may be exposed to multi-ionic aqueous environments over their lifetime, a potential degradation mode of the outer layer could be environmentally assisted cracking (EAC). The objective of the current research is to characterize the effect of applied potential and temperature on the susceptibility of Alloy 22 to EAC in simulated concentrated water (SCW) using the slow strain rate test (SSRT). Results show that Alloy 22 may suffer EAC at applied potentials approximately 400 mV more anodic than the corrosion potential (Ecorr).

scholarly journals A Phenomenological Approach to Simulating the Evolution of Radioactive-Waste Container Damage Due to Pitting Corrosion

1995 ◽  
Vol 412 ◽  
Author(s):  
G. A. Henshall
Keyword(s):  
Radioactive Waste ◽  
Pitting Corrosion ◽  
Current Model ◽  
Laboratory Data ◽  
Phenomenological Approach ◽  
Surface Areas ◽  
Waste Container ◽  
Pit Depth ◽  
Time Required ◽  
High Level

AbstractThe damage to high-level radioactive-waste containers by pitting corrosion is an important design and performance assessment consideration. It is desirable to calculate the evolution of the pit depth distribution, not just the time required for initial penetration of the containers, so that the area available for release of radionuclides through the container can be estimated. A phenomenological approach for computing the time evolution of these distributions is presented which combines elements of the deterministic and stochastic aspects of pit growth. The consistency of this approach with the mechanisms believed to control the evolution of the pit depth distribution is discussed. Qualitative comparisons of preliminary model predictions with a variety of experimental data from the literature are shown to be generally favorable. The sensitivity of the simulated distributions to changes in the input parameters is discussed. Finally, the results of the current model are compared to those of existing approaches based on extremevalue statistics, particularly regarding the extrapolation of laboratory data to large exposed surface areas.

High Strength FeCo–V Intermetallic Alloy: Electrical and Magnetic Properties

2005 ◽  
Vol 20 (6) ◽  
pp. 1515-1522 ◽  
Author(s):  
R.S. Sundar ◽  
S.C. Deevi ◽  
B.V. Reddy
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Room Temperature ◽  
Age Hardening ◽  
High Coercivity ◽  
Aged Alloy ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
Hardening Behavior

Age-hardening behavior of a new generation of FeCo alloys [Fe–40Co–5V–0.005B–0.015C–0.5Mo–0.5Nb (at.%)] is characterized by microhardness, tensile testing, electrical resistivity, and magnetic properties. The alloy exhibits maximum hardening when aged at 600 °C. Precipitation of γ2 (V-rich face-centered cubic phase) during aging appears to be responsible for the observed hardening behavior. The alloy exhibits superior creep resistance when subjected to solutionizing in γ phase field and aged at 600 °C. On the other hand, the room temperature tensile ductility of the aged alloy depends on the grain size, which in turn can be controlled by varying the solutionizing condition. The age-hardened alloy exhibits a room temperature electrical resistivity of 70–75 μΩ cm. The higher resistivity of the present alloy as opposed to the commercial FeCo–2V alloys is attributed to the high V content of the alloy. Structure-sensitive magnetic properties like coercivity and core losses of the alloy are affected by the aging treatment, and the maximum coercivity is observed when the alloy is aged at 600 °C. High coercivity of the alloy is attributed to the fine distribution of paramagnetic γ2 precipitate, fine grain size, and internal stress arising from phase transformation.

scholarly journals Electrochemical Preparation of Fe0.5CoNiCuSnx Medium Entropy Alloys and Their Corrosion Properties

2021 ◽  
Author(s):  
Jian Huang ◽  
Peilin Wang ◽  
Kaifa Du ◽  
Huayi Yin ◽  
Dihua Wang
Keyword(s):  
Corrosion Resistance ◽  
Inert Anode ◽  
Corrosion Current ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
Corrosion Properties ◽  
Preparation Methods ◽  
Electrochemical Preparation ◽  
Green Approach ◽  
Resistant Medium

Abstract The exploration of efficient preparation methods and corrosion-resistant medium entropy alloys (MEAs) has attracted significant attentions in recent years. In this paper, powdery Fe0.5CoNiCuSnx (x=0, 0.05, 0.08, and 0.1) MEAs were prepared by the one-step electrochemical reduction of metal oxides in molten Na2CO3-K2CO3 using a Ni11Fe10Cu oxygen-evolution inert anode. The effects of Sn on the structures, morphologies, and corrosion behaviors of the prepared MEAs were systematically investigated. The electrolytic MEAs exhibited a single face-centered cubic phase at x≤0.05, and the CuSn-rich phase would be segregated in the alloys at 0.08≤x≤0.1. Moreover, increasing Sn reduced the particles size of MEAs, and Sn improved the corrosion resistance of MEAs in 0.5 M H2SO4, 1 M KOH, and 3.5% NaCl solutions. The electrolytic MEA(Sn0.05) exhibited the best corrosion resistance, which had the corrosion current densities of 3.7×10-5 A/cm2 (0.5 M H2SO4), 1.2×10-5 A/cm2 (1 M KOH), and 1.6×10-5 A/cm2 (3.5 wt% NaCl) at room temperature. Overall, this paper not only provides a green approach to preparing Sn-containing MEAs, but also offers an efficient way to control structures and morphologies, thereby improving the corrosion resistance.

ПРАГМАТИЧНИЙ ПОТЕНЦІАЛ НАТИВНОЇ РЕКЛАМИ: ФОРМИ, ТРЕНДИ (НА ПРИКЛАДІ НАТИВНОГО КОНТЕНТУ В СОЦІАЛЬНІЙ МЕРЕЖІ FACEBOOK ЩОДО БРЕНДА ФАКУЛЬТЕТУ ЖУРНАЛІСТИКИ ЗНУ)

2020 ◽  
pp. 113
Author(s):  
V. Kovpak ◽  
N. Trotsenko
Keyword(s):  
Social Network ◽  
Professional Training ◽  
Educational Process ◽  
Communication Strategy ◽  
Student Centered ◽  
Teacher Student ◽  
The Social ◽  
National University ◽  
High Level ◽  
The Impact

<div><p><em>The article analyzes the peculiarities of the format of native advertising in the media space, its pragmatic potential (in particular, on the example of native content in the social network Facebook by the brand of the journalism department of ZNU), highlights the types and trends of native advertising. The following research methods were used to achieve the purpose of intelligence: descriptive (content content, including various examples), comparative (content presentation options) and typological (types, trends of native advertising, in particular, cross-media as an opportunity to submit content in different formats (video, audio, photos, text, infographics, etc.)), content analysis method using Internet services (using Popsters service). And the native code for analytics was the page of the journalism department of Zaporizhzhya National University on the social network Facebook. After all, the brand of the journalism department of Zaporozhye National University in 2019 celebrates its 15th anniversary. The brand vector is its value component and professional training with balanced distribution of theoretical and practical blocks (seven practices), student-centered (democratic interaction and high-level teacher-student dialogue) and integration into Ukrainian and world educational process (participation in grant programs).</em></p></div><p><em>And advertising on social networks is also a kind of native content, which does not appear in special blocks, and is organically inscribed on one page or another and unobtrusively offers, just remembering the product as if «to the word». Popsters service functionality, which evaluates an account (or linked accounts of one person) for 35 parameters, but the main three areas: reach or influence, or how many users evaluate, comment on the recording; true reach – the number of people affected; network score – an assessment of the audience’s response to the impact, or how far the network information diverges (how many share information on this page).</em></p><p><strong><em>Key words:</em></strong><em> nativeness, native advertising, branded content, special project, communication strategy.</em></p>

THE IMPACT OF UKRAINE'S EXCISE DUTY POLICY ON THE TRANSFORMATION PROCESSES OF THE TOBACCO MARKET

2020 ◽  
Vol 2020 (10) ◽  
pp. 19-33
Author(s):  
Nadiia NOVYTSKA ◽  
◽  
Inna KHLIEBNIKOVA ◽  
Keyword(s):  
Structural Changes ◽  
Tax Avoidance ◽  
Transformation Process ◽  
State Regulation ◽  
Tobacco Products ◽  
Excise Duty ◽  
Increasing Demand ◽  
High Level ◽  
The Impact ◽  
Transformation Processes

The market of tobacco products in Ukraine is one of the most dynamic and competitive. It develops under the influence of certain factors that cause structural changes, therefore, the aim of the article is to conduct a comprehensive analysis of transformation processes in the market of tobacco and their alternatives in Ukraine and identify the factors that cause them. The high level of tax burden and the proliferation of alternative products with a potentially lower risk to human health, including heating tobacco products and e-cigarettes, are key factors in the market’s transformation process. Their presence leads to an increase in illicit turnover of tobacco products, which accounts for 6.37% of the market, and the gradual replacement of cigarettes with alternative products, which account for 12.95%. The presence on the market of products that are not taxed or taxed at lower rates is one of the reasons for the reduction of excise duty revenues. According to the results of 2019, the planned indicators of revenues were not met by 23.5%. Other reasons for non-fulfillment of excise duty revenues include: declining dynamics of the tobacco products market; reduction in the number of smokers; reorientation of «cheap whites» cigarette flows from Ukraine to neighboring countries; tax avoidance. Prospects for further research are identified, namely the need to develop measures for state regulation and optimization of excise duty taxation of tobacco products and their alternatives, taking into account the risks to public health and increasing demand of illegal products.

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