scholarly journals Microstructure and Properties of Selected Magnesium-Aluminum Alloys Prepared for SPD Processing Technology

2017 ◽  
Vol 62 (4) ◽  
pp. 2365-2370 ◽  
Author(s):  
L. Cizek ◽  
S. Rusz ◽  
O. Hilser ◽  
R. Śliwa ◽  
D. Kuc ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloys ◽  
Magnesium Alloys ◽  
Elevated Temperatures ◽  
Deformation Behaviour ◽  
Az91 Alloy ◽  
Test Results ◽  
Treatment Conditions ◽  
Composition Modification ◽  
Cast Magnesium

AbstractA growing interest in wrought magnesium alloys has been noticed recently, mainly due to development of various SPD (severe plastic deformation) methods that enable significant refinement of the microstructure and – as a result – improvement of various functional properties of products. However, forming as-cast magnesium alloys with the increased aluminum content at room temperature is almost impossible. Therefore, application of heat treatment before forming or forming at elevated temperature is recommended for these alloys. The paper presents the influence of selected heat treatment conditions on the microstructure and the mechanical properties of the as-cast AZ91 alloy. Deformation behaviour of the as-cast AZ61 alloy at elevated temperatures was analysed as well. The microstructure analysis was performed by means of both light microscopy and SEM. The latter one was used also for fracture analysis. Moreover, the effect of chemical composition modification by lithium addition on the microstructure of the AZ31-based alloy is presented. The test results can be helpful in preparation of the magnesium-aluminum alloys for further processing by means of SPD methods.

Mechanical Performance Evaluation of Cast Magnesium Alloys for Automotive and Aeronautical Applications

2006 ◽  
Vol 129 (3) ◽  
pp. 422-430 ◽  
Author(s):  
Sp. G. Pantelakis ◽  
N. D. Alexopoulos ◽  
A. N. Chamos
Keyword(s):  
Aluminum Alloys ◽  
Magnesium Alloys ◽  
Quality Index ◽  
Mechanical Performance ◽  
Cast Aluminum ◽  
Treatment Conditions ◽  
Cast Aluminum Alloys ◽  
Structural Applications ◽  
Cast Magnesium Alloys ◽  
Cast Magnesium

The potential of cast magnesium alloys for being used as structural materials in lightweight applications is assessed. The ability of the alloys for mechanical performance is evaluated and compared against the ability of widely used structural aircraft cast aluminum alloys. The specific quality index QDS, devised for evaluating both cast and wrought aluminum alloys, will be exploited to evaluate the ability of a number of cast magnesium alloys for mechanical performance. The exploited quality index QDS involves the material’s yield strength Rp to account for strength, the strain energy density W to account for both tensile ductility and toughness, and the material’s density ρ. The effects of differences in chemical composition and heat treatment conditions on the mechanical performance of cast magnesium alloys have been assessed. The use of the quality index QDS has been proved to appreciably facilitate the evaluation of the mechanical performance of cast magnesium alloys and also the comparison between alloys of different base materials. The results quantify the gap to be closed such as to involve cast magnesium alloys in aircraft structural applications.

Continuous Casting of Magnesium Billets for Semi-Solid Processing

2005 ◽  
Vol 475-479 ◽  
pp. 517-520
Author(s):  
Hwa Chul Jung ◽  
Kwang Seon Shin
Keyword(s):  
Aluminum Alloys ◽  
Continuous Casting ◽  
Magnesium Alloys ◽  
Casting Process ◽  
Az91 Alloy ◽  
Attractive Alternative ◽  
Limited Information ◽  
Continuous Casting Process ◽  
Dendritic Microstructure ◽  
Semi Solid

Semi-solid processing is recognized as an attractive alternative method for the near net-shape production of engineering components. Although there has been a significant progress in semi-solid processing of aluminum alloys, very limited information is available on semi-solid processing of magnesium alloys, except for the thixomolding process. Continuous casting process has been utilized to produce the billets with the desirable cross-section at a reduced production cost for many metals, such as steel, copper and aluminum alloys. It has also been commercially utilized to produce the aluminum billets with non-dendritic microstructure for subsequent thixocasting process. However, continuous casting of magnesium billets for semi-solid processing has not yet been commercialized due to the difficulties involved in casting of magnesium alloys. In the present study, a continuous casting process has been developed for the production of the cylindrical billets of magnesium alloys for the subsequent thixocasting process. In order to obtain the desired non-dendritic microstructure with an excellent degree of homogeneity both in microstructure and composition, an electromagnetic stirring system has been utilized. A continuous casting process has been proven to be an efficient way to produce the high quality billets of magnesium alloys for semi-solid processing. A prototype air conditioner cover was produced using the continuously cast billets of AZ91 alloy.

Influence of Heat Treatment on Structure and Properties of the Cast Magnesium Alloys

2006 ◽  
Vol 15-17 ◽  
pp. 491-496 ◽  
Author(s):  
Tomasz Tański ◽  
Leszek Adam Dobrzański ◽  
Lubomír Čížek
Keyword(s):  
Heat Treatment ◽  
Chemical Composition ◽  
Magnesium Alloys ◽  
Diffraction Method ◽  
Hardness Measurement ◽  
X Ray ◽  
Qualitative And Quantitative ◽  
Cast Alloys ◽  
Cast Magnesium Alloys ◽  
Cast Magnesium

In this paper is presented the structure and proprieties of the cast magnesium alloys as cast state and after heat treatment cooled with different cooling rate, depending on the cooling medium (furnace, water, air). For investigations samples in shape of 250x150x25 mm plates were used. The presented results concern X-ray qualitative and quantitative microanalysis as well as qualitative and quantitative X-ray diffraction method, tensile tests, hardness measurement. In the analysed alloys a structure of α %solid solution and fragile phase β (Mg17Al12) occurred mainly on grain borders as well as eutectic and phase AlMnFe, Mg2Si. Investigation are carried out for the reason of chemical composition influence and precipitation processes influence to the structure and mechanical properties of the magnesium cast alloys with different chemical composition in as cast alloys and after heat treatment.

scholarly journals Mechanical Properties of WE43 Magnesium Alloy Joint at Elevated Temperature / Właściwości Mechaniczne Złączy Ze Stopu Magnezu WE43 W Podwyższonej Temperaturze

2015 ◽  
Vol 60 (4) ◽  
pp. 2695-2702 ◽  
Author(s):  
A. Turowska ◽  
J. Adamiec
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Magnesium Alloy ◽  
Welded Joints ◽  
Elevated Temperatures ◽  
Base Material ◽  
Casting Process ◽  
Operating Conditions ◽  
Cast Magnesium ◽  
We43 Alloy

The WE43 cast magnesium alloy, containing yttrium and rare earth elements, remains stable at temperatures up to 300°C, according to the manufacturer, and therefore it is considered for a possible application in the aerospace and automotive. Usually, it is cast gravitationally into sand moulds and used for large-size castings that find application in the aerospace industry. After the casting process any possible defects that might appear in the casting are repaired with the application of welding techniques. These techniques also find application in renovation of the used cast elements and in the process of joining the cast parts into complex structures. An important factor determining the validity of the application of welding techniques for repairing or joining cast magnesium alloys is the structural stability and the stability of the properties of the joint in operating conditions. In the literature of the subject are information on the properties of the WE43 alloy or an impact of heat treatment on the structure and properties of the alloy, however, there is a lack of information concerning the welded joints produced from this alloy. This paper has been focused on the analysis the microstructure of the welded joints and their mechanical properties at elevated temperatures. To do this, tensile tests at temperatures ranging from 20°C to 300°C were performed. The tests showed, that up to the temperature of 150°C the crack occurred in the base material, whereas above this temperature level the rapture occurred within the weld. The loss of cohesion resulted from the nucleation of voids on grain boundaries and their formation into the main crack. The strength of the joints ranged from 150 MPa to 235 MPa, i.e. around 90 % of strength of the WE43 alloy after heat treatment (T6). Also performed a profilometric examination was to establish the shape of the fracture and to analyze how the temperature affected a contribution of phases in the process of cracking. It was found that the contribution of intermetallic phases in the process of cracking was three times lower for cracks located in the area of the weld.

Studies Concerning the Hardening Capacity of Aluminium Alloys through Heat Treatment in Electromagnetic Field

2007 ◽  
Vol 23 ◽  
pp. 201-204
Author(s):  
Maria Stoicănescu ◽  
I. Giacomelli ◽  
Maria Simona Pantelimon
Keyword(s):  
Heat Treatment ◽  
Electromagnetic Field ◽  
Aluminum Alloys ◽  
Electromagnetic Fields ◽  
Aluminium Alloys ◽  
Final Heat Treatment ◽  
Final Heat ◽  
Long Period ◽  
Hardening Process ◽  
Treatment Conditions

It is well known that the aluminum alloys containing Cu and/or Mg lead to soluble compounds which themselves allow the hardening during the process of strengthening and ageing. At the same time, the hardening process during ageing takes a relatively long period of time, and the registered rises are generally not too high. There are presented studies regarding to alloy AlCu4Mg1,5Mn which was tested in several heat treatment conditions. These alloy, after final heat treatment of hardness by and ageing, suffers a sensitive hardening – the ageing is recommended for pieces used under medium and intense mechanical stresses Using the alternative electromagnetic fields is more efficient by 10 to 12% than stationary one, not only regarding to the period of ageing, but also regarding to the highest values of hardness; Also other specific results are given in the paper.

Experimental Investigation of the Local Deformation Behaviour of MMCs

2005 ◽  
Vol 482 ◽  
pp. 211-214 ◽  
Author(s):  
Klaus Unterweger ◽  
Otmar Kolednik
Keyword(s):  
Heat Treatment ◽  
Deformation Behaviour ◽  
Damage Mechanism ◽  
Local Deformation ◽  
Deformation Analysis ◽  
Particle Fracture ◽  
Aged Material ◽  
Treatment Conditions ◽  
Particle Damage ◽  
Particle Debonding

Particle reinforced MMCs with a particle size of 100µm and an aluminium matrix (Al6061) are analyzed by the means of automatic local deformation analysis. Two different heat treatment conditions (under- and over-aged) are investigated. It is found that the local deformation behaviour is strongly determined by particle damage. While the under-aged material shows only particle fracture, the over-aged MMC shows also particle debonding as a relevant damage mechanism.

Effect of Heat Treatment Conditions on Tube Hydroforming Characteristics of Aluminum Alloy

2013 ◽  
Vol 535-536 ◽  
pp. 275-278
Author(s):  
Myeong Han Lee ◽  
Young Chul Shin ◽  
Duk Jae Yoon
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Metal Forming ◽  
Tube Hydroforming ◽  
Treatment Processes ◽  
Forming Technology ◽  
Treatment Conditions ◽  
Compressive Loads ◽  
Hydroforming Process

Tube hydroforming is a metal forming technology that utilizes internal pressure and axial compressive loads to generate designed product shapes with complex sections from tubular materials. The tube hydroforming process has been used in the automotive, aircraft, and bicycle industries for many years. With the pursuit of lighter bicycles, aluminum alloys have been utilized as an alternative to steel. To obtain adequate strength, the aluminum alloys should undergo heat treatment processes before being used. However, the mechanical properties of the alloys vary with the tempering conditions. This paper aims to evaluate the effects of tube hydroforming characteristics on different kinds of tempered aluminum alloys. Based on numerical simulations, suitable tube hydroforming processing conditions for each tempered aluminum alloy are suggested.

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