Structure Analysis of Magnesium Alloy (AZ31) Wires at Different Stages of a Multistage Cold Drawing Process

2016 ◽  
Vol 682 ◽  
pp. 125-131
Author(s):  
Teresa Bajor
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Cold Drawing ◽  
Automotive Electronics ◽  
Drawing Process ◽  
Initial State ◽  
Before And After ◽  
The Subject ◽  
The Impact

The formability of magnesium alloys is the subject of efforts undertaken in many research centers due to their outstanding mechanical, plastic, and above all, physical properties. For this reason, magnesium alloys have become an important material which finds broad possibilities for application in many industries: automotive, electronics, aerospace and so on.The paper presents an analysis of changes in structure of AZ31 magnesium alloy wire cold-deformed in the drawing process using interoperate heat treatment. Microstructure observations of the wire by means of optical microscopy were performed in initial state, after each drawing process, and before and after heat treatment. The studies regarding the impact of selected variants of deformation on microstructure were also carried out at the scanning electron microscope (SEM).

Characteristics of the G200CrNiMo4-3-3 Cast Steel in as Cast State

2015 ◽  
Vol 641 ◽  
pp. 136-140
Author(s):  
Edyta Rożniata ◽  
Janusz Krawczyk ◽  
Robert Dąbrowski ◽  
Jerzy Pacyna
Keyword(s):  
Heat Treatment ◽  
Impact Test ◽  
Cast Steel ◽  
Initial Material ◽  
Cast State ◽  
Initial State ◽  
The Subject ◽  
The Impact ◽  
Cast Condition ◽  
Fracture Work

The subject of investigations constituted the G200CrNiMo4-3-3 cast steel applied for metallurgical rolls. This is the material, which microstructure can be modified by the heat treatment. The presented hereby work concerns the initial state (as cast condition) of the investigated cast steel. This cast steel constitutes the initial material for the heat treatment. The morphology of carbide precipitates, including the cementite precipitated on grain boundaries of the primary austenite, hypereutectoid cementite precipitated in the Widmannstӓtten system and lederburitic cementite, were characterised in the study. The results of investigations of mechanical and fractographic properties of the G200CrNiMo4-3-3 cast steel, were also presented. Among others, the values of fracture work in the impact test, fracture toughness (KIc) and wear resistance were given. The crack pathway together with the hypereutectoid cementite fraction role in its development, was presented. The obtained investigation results, presented in the hereby paper, will constitute the comparison base for the assessment of the heat treatment influence on the microstructure and properties of the tested G200CrNiMo4-3-3 cast steel.

Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

The Israeli–Lebanese war of 2006: consequences for Lebanon

2008 ◽  
Vol 1 (2) ◽  
pp. 187-210
Author(s):  
Ziad Hafez
Keyword(s):  
Arab Countries ◽  
The Political ◽  
National Unity ◽  
Major Consequence ◽  
Political Narrative ◽  
Defence Policy ◽  
Before And After ◽  
The Usa ◽  
The Subject ◽  
The Impact

This article focuses on the political narrative in Lebanon before and after the Israeli war against Lebanon in 2006. It revolves around the subject of national unity as a sine qua non condition for success for the Lebanese resistance led by Hezbollah. A major consequence of the narrative on national unity is the need to build a modern state and establish a cohesive defence policy. The paper also examines the impact of the war on Lebanon's economy and on its relations with the rest of the world (the USA, France, Syria, Arab countries, and Iran).

scholarly journals Maths Sparks engagement programme: investigating the impact on under-privileged pupils’ attitudes towards mathematics

2020 ◽  
Author(s):  
Aoibhinn Ni Shuilleabhain ◽  
Anthony Cronin ◽  
Mark Prendergast
Keyword(s):  
Social Research ◽  
Time Frame ◽  
Mathematics Students ◽  
Undergraduate Mathematics ◽  
High Stakes ◽  
Mathematical Concepts ◽  
Attitudes Towards Mathematics ◽  
Before And After ◽  
The Subject ◽  
The Impact

Abstract In this paper we explore the attitudes of under-privileged secondary school pupils in Ireland towards mathematics and investigate the impact of attending a 4-week engagement programme on these attitudes. The pupils involved in this research attended schools recognized by the Department of Education & Skills as socio-economically deprived. Pupils attending these schools, known as Delivering Equality of Opportunity in Schools (DEIS), are 40% less likely than their counterparts in non-DEIS schools to pursue mathematics at a higher level in state examinations (Smyth, E., Mccoy, S. & Kingston, G., 2015, Learning From the Evaluation of DEIS. Dublin: Economic and Social Research Institute). However, little research has reported on these pupils’ experiences of and attitudes towards mathematics at senior secondary level. An engagement programme entitled ‘Maths Sparks’ was purposefully designed for secondary pupils from DEIS schools, with the aim of positively influencing their attitudes towards and confidence in mathematics. The programme consisted of weekly out-of-school workshops exploring extra-curricular mathematics topics, designed and delivered by undergraduate mathematics students. Questionnaires were utilized to evaluate pupils’ attitudes towards mathematics before and after their participation in the programme. Despite its relatively short time frame, qualitative and quantitative analysis suggests an increase in participating pupils’ attitudes towards, enjoyment of and self-confidence in mathematics due to their participation in the programme. Findings also suggest that while these pupils liked the subject of mathematics, their experience of learning the subject in school was not always positive and was sometimes hindered by the absence of higher-level mathematics as an option in school. The high-stakes examination content and teachers’ beliefs in the ability of their students also sometimes negatively impacted learners’ intentions to pursue mathematics at a higher level. Findings suggest that longitudinal mathematics engagement programmes, which focus on problem solving, involve extra-curricular mathematical concepts and are presented by undergraduate mathematics students, may provide a valuable way of positively impacting pupils’ intentions to pursue the subject.

Effect of Heat Treatment on Tensile Strength and Microstructure of AZ61A Magnesium Alloy

2014 ◽  
Vol 606 ◽  
pp. 55-59 ◽  
Author(s):  
R. Senthil ◽  
A. Gnanavelbabu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Mg Alloys ◽  
Forming Process ◽  
Microstructural Parameters ◽  
Heat Treated ◽  
Mutual Relations

Magnesium alloys are the very progressive materials whereon is due to improve their end-use properties. Especially, wrought Mg alloys attract attention since they have more advantageous mechanical properties than cast Mg alloys. Investigations were carried out the effects of heat treatment on tensile strength and microstructure of AZ61A magnesium alloy. The AZ61A Mg alloy is solution heat treated at the temperature of 6500F (343°C) for various soaking timing such as 120 min, 240 min and 360 minutes and allowed it cool slowly in the furnace itself. Magnesium alloys usually are heat treated either to improve mechanical properties or as means of conditioning for specific fabrication operations. Special attention had been focused on the analysis of mutual relations existing between the deformation conditions, microstructural parameters, grain size and the achieved mechanical properties. The result after the solution heat treatment, showed remarkably improved hardness, tensile strength and yield strength. It would be appropriate for a forming process namely isostatic forming process.

Incremental Forming for Aluminum Automotive Technology

2005 ◽  
Author(s):  
Sergey F. Golovashchenko ◽  
Al Krause ◽  
Alan J. Gillard
Keyword(s):  
Heat Treatment ◽  
Microstructural Analysis ◽  
Material Structure ◽  
Treatment Regimes ◽  
Before And After ◽  
The Subject ◽  
Deformation And Heat Treatment ◽  
Automotive Panels ◽  
Heat Treatment Regimes ◽  
Complex Parts

Insufficient formability can be a major issue in the manufacturing of complex parts, particularly in aluminum alloys that have less formability when compared to steel. The approach which is the subject of this work is to determine the technical feasibility of partial forming, followed by a fast heat treatment and then further deformation. Alloys for consideration would include both 5xxx and 6xxx alloys typically used on interior and exterior automotive panels. The heat treatment regimes used for 6xxx alloys did not affect the material structure, which was confirmed by microstructural analysis and comparison of mechanical properties before and after the heat treatment. Experiments on 5xxx alloys indicated relative improvement of 300% or more. Regimes of material deformation and heat treatment will be presented.

The impact of financial safety act and corporate governance on the level of financial disclosure

2016 ◽  
Vol 58 (6) ◽  
pp. 618-633 ◽  
Author(s):  
Ali Ahmadi ◽  
Abdelfettah Bouri
Keyword(s):  
Corporate Governance ◽  
Design Methodology ◽  
Stock Exchange ◽  
Financial Disclosure ◽  
Content Type ◽  
Study Results ◽  
Before And After ◽  
The Subject ◽  
High Level ◽  
The Impact

Purpose This research paper aims to identify and measure the contribution of the financial safety act (FSA) regulation in improving the level of financial disclosure of listed Tunisian firms. To answer the problems of the subject, the authors tried to hold accountable several determinants of the level of financial disclosure relating to the particular characteristics of the firm, and the adoption of the recommendations envisaged by the FSA, as likely to have an impact on the level of financial disclosure of Tunisian firms. Design/methodology/approach With a sample composed by 20 companies during the period from 2003 to 2010 (160 observations), the contribution of the FSA regulation in improving the level of financial disclosure of listed Tunisian firms was identified and measured. After that, the levels of financial disclosure before and after the FSA were compared. Findings The study results confirm the positive and significant effect of the FSA on the level of financial disclosure. This impact seems to appear through the improvement of the disclosure level during the years which follow the adoption of the new regulation. The results of this study also show that firms with a high level of financial disclosure are those which have an independent board of directors, auditor BIG and joint audit. Originality/value This paper is devoted to evaluate the impact of the FSA n°2005-96 and corporate governance on the level of financial disclosure. The empirical study relates to a sample of 20 firms listed on the Tunis Stock Exchange observed over the period 2003-2010.

Characterization of Ni-P and Ni-P-Al2O3 Heat Treated Layers

2017 ◽  
Vol 1143 ◽  
pp. 26-31
Author(s):  
Lucica Balint ◽  
Gina Genoveva Istrate
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Corrosion Resistance ◽  
Composite Coatings ◽  
Treatment Temperature ◽  
Initial State ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Before And After

Research has shown the relationship among hardness, usage and corrosion resistance Ni-P-Al2O3 composite coatings on steel support heat treated. The electroless strips were heat treated at 200°C, 300°C, 400°C, 500°C and 600°C. Further studies on corrosion, hardness and usage revealed changes in properties, compared to the initial state, both on the strips coated with Ni-P and the ones coated with Ni-P-Al2O3 composite. The samples have been studied before and after the heat treatment via Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Analysis (EDX) and X-Ray Diffraction (XRD). The results show that untreated Ni-P layers exhibit strong corrosion resistance, while hardness and usage increase with heat treatment temperature, with a peak at 400 °C. Using suspended particles co-deposition, led to new types of layers, some with excellent hardness and usage properties. Corrosion resistance increase with heat treatment. Coating layers can be adjusted to the desired characteristics, by selecting proper parameters for the expected specific results.

scholarly journals Effect of Heat Treatment on Microstructure and Impact Toughness of Ti-6Al-4V Manufactured by Selective Laser Melting Process

2017 ◽  
Vol 62 (2) ◽  
pp. 1341-1346 ◽  
Author(s):  
K.-A. Lee ◽  
Y.-K. Kim ◽  
J.-H. Yu ◽  
S.-H. Park ◽  
M.-C. Kim
Keyword(s):  
Heat Treatment ◽  
Impact Toughness ◽  
Selective Laser Melting ◽  
Impact Energy ◽  
Charpy Impact ◽  
Melting Process ◽  
Laser Melting ◽  
Average Impact ◽  
Before And After ◽  
The Impact

AbstractThis study manufactured Ti-6Al-4V alloy using one of the powder bed fusion 3D-printing processes, selective laser melting, and investigated the effect of heat treatment (650°C/3hrs) on microstructure and impact toughness of the material. Initial microstructural observation identified prior-βgrain along the building direction before and after heat treatment. In addition, the material formed a fully martensite structure before heat treatment, and after heat treatment,αandβphase were formed simultaneously. Charpy impact tests were conducted. The average impact energy measured as 6.0 J before heat treatment, and after heat treatment, the average impact energy increased by approximately 20% to 7.3 J. Fracture surface observation after the impact test showed that both alloys had brittle characteristics on macro levels, but showed ductile fracture characteristics and dimples at micro levels.

scholarly journals Application of Industrial Computer Tomography to Determine Wood Porosity

2021 ◽  
Vol 29 (49) ◽  
pp. 15-23
Author(s):  
Eva Buranská ◽  
Peter Rantuch ◽  
Ivan Buranský ◽  
Alexandra Kucmanová
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Computer Tomography ◽  
Subject Matter ◽  
Total Porosity ◽  
Light Metal ◽  
Paulownia Tomentosa ◽  
Before And After ◽  
The Subject ◽  
Non Destructive

Abstract The main objective of this research was to analyse the limitations of iCT - industrial computer tomography for measuring the wood pores characteristics as a new non-destructive method which is primarily intended to measure and inspect complete components primarily made of plastics or light metal. The subject matter of this paper are wood samples of paulownia (Paulownia tomentosa) and ash (Fraxinus excelsior) before and after thermal treatment. Porosity, pore volume and distribution of pores on the wood samples before and after the heat treatment were measured by iCT Metrotom 1500. The total porosity of the samples before thermal treatment was 5.28 % (paulownia) and 14.90 % (ash), while after thermal treatment, porosity increased to 9.50 % (paulownia) and to 30.78 % (ash). Changes in the porosity of the samples before and after heat treatment show an increase in porosity of 3.87 % (paulownia) and 15.88 % (ash).

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