scholarly journals A Constitutive Model for Yield Strength and Work Hardening Behaviour of Aluminium Alloys during Artificial Ageing

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1094
Author(s):  
Kang Ji ◽  
Guanfeng Li ◽  
Yongbao Sun ◽  
Jia Xu ◽  
Hui Chen ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Yield Strength ◽  
Constitutive Model ◽  
Work Hardening ◽  
Aluminium Alloys ◽  
Ageing Process ◽  
Artificial Ageing ◽  
Different Types ◽  
Primary Dimension

In this study, a unified constitutive model has been developed for both yield strength and work hardening behaviour prediction of aluminium alloys with different types of precipitates during and after artificial ageing. The different type and dimensions of general precipitate shapes (sphere, plate, rod) have been classified and modelled by a primary dimension and aspect ratio, with which a general set of equations has been utilised to model the precipitates evolutions during ageing of various aluminium alloys. In addition, the effects of main microstructures on not only yield strength but also work-hardening behaviour of artificially aged aluminium alloys have been considered and modelled, based on which, a whole set of unified constitutive model considering both micro- and macro-properties for long-term artificial ageing of aluminium alloys has been proposed. Artificial ageing of two representative aluminium alloys (an Al-Mg-Si alloy AA6063 and an Al-Cu-Li alloy AA2198) has been adopted to show the capability and effectiveness of the developed model. The results show that the model can successfully predict the microstructures, yield strength and work hardening behaviour of various aluminium alloys with different precipitate types after long-term artificial ageing process, e.g., from 0 h to 500 h. It is believed that the model can be used for ageing of other aluminium alloys with dominant sphere, plate or rod-shaped precipitates.

COMPUTER MODELLING OF AGE HARDENING FOR ISOTHERMALLY AGED Al-Mg-Si ALLOYS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4177-4182 ◽  
Author(s):  
LINDA WU ◽  
W. GEORGE FERGUSON
Keyword(s):  
Yield Strength ◽  
Aluminium Alloys ◽  
Input Data ◽  
Present Model ◽  
Computer Modelling ◽  
Age Hardening ◽  
Artificial Ageing ◽  
Casting Alloys ◽  
Different Temperatures ◽  
Isothermal Ageing

Computer modelling, due to it saving time and money, has been widely used in industrial simulation. The present model, which is based on the Shercliff-Ashby methodology for the ageing of aluminum alloys, can be used to predict the yield strength (or hardness) of Al - Mg - Si alloys for the artificial ageing temperature below the solvus temperature as a function of time. With suitable input data, this model can be applied to most Al - Mg - Si alloys, wrought or cast. In the present model, input data for aluminium alloys of A356, A357 and 6061 is taken from the open literature, and then the unknown constants are calibrated from these data. After calibration, the ageing curves are constructed for different isothermal ageing temperatures. Finally, experimentally ageing heat treatments at different temperatures for casting alloys of A356 were done to validate the model.

The Acute Effect of Alcohol on Various Memory Processes

2010 ◽  
Vol 24 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Márk Molnár ◽  
Roland Boha ◽  
Balázs Czigler ◽  
Zsófia Anna Gaál
Keyword(s):  
Low Dose ◽  
Short Term Memory ◽  
Acute Effect ◽  
Long Term Memory ◽  
Term Memory ◽  
Memory Processes ◽  
Different Types ◽  
The Brain ◽  
Legal Consequences

This review surveys relevant and recent data of the pertinent literature regarding the acute effect of alcohol on various kinds of memory processes with special emphasis on working memory. The characteristics of different types of long-term memory (LTM) and short-term memory (STM) processes are summarized with an attempt to relate these to various structures in the brain. LTM is typically impaired by chronic alcohol intake but according to some data a single dose of ethanol may have long lasting effects if administered at a critically important age. The most commonly seen deleterious acute effect of alcohol to STM appears following large doses of ethanol in conditions of “binge drinking” causing the “blackout” phenomenon. However, with the application of various techniques and well-structured behavioral paradigms it is possible to detect, albeit occasionally, subtle changes of cognitive processes even as a result of a low dose of alcohol. These data may be important for the consideration of legal consequences of low-dose ethanol intake in conditions such as driving, etc.

Effect of sleep on memory for binding different types of visual information

2020 ◽  
Author(s):  
John J Shaw ◽  
Zhisen Urgolites ◽  
Padraic Monaghan
Keyword(s):  
Visual Information ◽  
Storage Capacity ◽  
Declarative Memory ◽  
Recognition Task ◽  
Forced Choice ◽  
Long Term Memory ◽  
Term Memory ◽  
Different Types ◽  
Types Of Information

Visual long-term memory has a large and detailed storage capacity for individual scenes, objects, and actions. However, memory for combinations of actions and scenes is poorer, suggesting difficulty in binding this information together. Sleep can enhance declarative memory of information, but whether sleep can also boost memory for binding information and whether the effect is general across different types of information is not yet known. Experiments 1 to 3 tested effects of sleep on binding actions and scenes, and Experiments 4 and 5 tested binding of objects and scenes. Participants viewed composites and were tested 12-hours later after a delay consisting of sleep (9pm-9am) or wake (9am-9pm), on an alternative forced choice recognition task. For action-scene composites, memory was relatively poor with no significant effect of sleep. For object-scene composites sleep did improve memory. Sleep can promote binding in memory, depending on the type of information to be combined.

USS DUAL PHASE 80

Alloy Digest ◽  
1978 ◽  
Vol 27 (12) ◽  
Keyword(s):  
United States ◽  
Corrosion Resistance ◽  
Yield Strength ◽  
Work Hardening ◽  
Steel Sheet ◽  
High Strength ◽  
Heat Treating ◽  
Dual Phase ◽  
United States Steel Corporation ◽  
Heavy Construction

Abstract USS Dual Phase 80 is a high-strength steel sheet which has a dual phase structure of martensite and ferrite. It provides all the benefits of higher strength with little sacrifice in ductility, formability or weldability. Dual Phase 80 gains strength as it is formed through rapid work hardening of its unique microstructure; in fact, it increases from its delivered yield strength of 50,000 psi up to 80,000 psi (or more) in forming. Its final strength depends on the amount of forming. Its many applications include automotive vehicles, farm equipment and heavy construction equipment. This datasheet provides information on composition, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-352. Producer or source: United States Steel Corporation.

scholarly journals Toxic or Not Toxic, That Is the Carbon Quantum Dot’s Question: A Comprehensive Evaluation with Zebrafish Embryo, Eleutheroembryo, and Adult Models

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1598
Author(s):  
Chih-Yu Chung ◽  
Yu-Ju Chen ◽  
Chia-Hui Kang ◽  
Hung-Yun Lin ◽  
Chih-Ching Huang ◽  
...  
Keyword(s):  
Zebrafish Embryo ◽  
Comprehensive Evaluation ◽  
Aquatic Organisms ◽  
Carbon Quantum Dots ◽  
Adult Zebrafish ◽  
Fish Embryo ◽  
Wide Range ◽  
Different Types ◽  
Low Toxicity

Carbon quantum dots (CQDs) are emerging novel nanomaterials with a wide range of applications and high biocompatibility. However, there is a lack of in-depth research on whether CQDs can cause acute or long-term adverse reactions in aquatic organisms. In this study, two different types of CQDs prepared by ammonia citrate and spermidine, namely CQDAC and CQDSpd, were used to evaluate their biocompatibilities. In the fish embryo acute toxicity test (FET), the LD50 of CQDAC and CQDSpd was about 500 and 100 ppm. During the stage of eleutheroembryo, the LD50 decreased to 340 and 55 ppm, respectively. However, both CQDs were quickly eliminated from embryo and eleutheroembryo, indicating a lack of bioaccumulation. Long-term accumulation of CQDs was also performed in this study, and adult zebrafish showed no adverse effects in 12 weeks. In addition, there was no difference in the hatchability and deformity rates of offspring produced by adult zebrafish, regardless of whether they were fed CQDs or not. The results showed that both CQDAC and CQDSpd have low toxicity and bioaccumulation to zebrafish. Moreover, the toxicity assay developed in this study provides a comprehensive platform to assess the impacts of CQDs on aquatic organisms in the future.

scholarly journals Case Study on Fire Resistance of Sandwiches for Means of Transport

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 207
Author(s):  
Pavel Koštial ◽  
Zora Koštialová Jančíková ◽  
Robert Frischer
Keyword(s):  
Fire Resistance ◽  
Fire Protection ◽  
Public Transport ◽  
Hybrid Vehicles ◽  
Safety Requirements ◽  
Different Types ◽  
Aluminum Honeycomb ◽  
Heat Loads

These days there are undeniably unique materials that, however, must also meet demanding safety requirements. In the case of vehicles, these are undoubtedly excellent fire protection characteristics. The aim of the work is to experimentally verify the proposed material compositions for long-term heat loads and the effect of thickness, the number of laminating layers (prepregs) as well as structures with different types of cores (primarily honeycomb made of Nomex paper type T722 of different densities, aluminum honeycomb and PET foam) and composite coating based on a glass-reinforced phenolic matrix. The selected materials are suitable candidates for intelligent sandwich structures, usable especially for interior cladding applications in the industry for the production of means of public transport (e.g., train units, trams, buses, hybrid vehicles).

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