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

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.

2005 ◽  
Vol 488-489 ◽  
pp. 397-400
Author(s):  
Hwa Chul Jung ◽  
Ye Sik Kim ◽  
Kwang Seon Shin

The demand for magnesium alloys has increased significantly during the past decade in the automotive and electronic industries where weight reduction becomes increasingly an important issue. At present, high-pressure die casting (HPDC) is a dominant process in production of magnesium alloy components. However, magnesium alloy components produced by HPDC suffer from porosity problem and this limits the enhancement of mechanical properties through subsequent heat treatments. The semi-solid processing (SSP) is an emerging new technology for near-net shape production of engineering components, in which the alloys are processed in the temperature range where the liquid and solid phases coexist. The SSP has various advantages over the conventional casting processes. It offers the castings with high integrity and less porosity and allows subsequent heat treatments for enhancement of mechanical properties. For these advantages, the SSP of magnesium alloys has received increasing attention in recent years. In the present study, the continuous casting process was developed for the production of magnesium billets for the subsequent SSP. The process utilizes an electromagnetic stirring system in order to obtain desired microstructure with an excellent degree of homogeneity in both microstructure and composition. Prototypes of an air conditioner cover and a telescope housing were produced using the SSP of the continuously cast magnesium alloy billets.


2012 ◽  
Vol 191 ◽  
pp. 183-188
Author(s):  
Agata Kierzek ◽  
Janusz Adamiec

The QE22 cast magnesium alloy containing silver, rare earth elements and zirconium is characterized by high mechanical properties and creep resistance of up to 200 ° C. It is cast gravitationally into sand moulds and permanent moulds. After the casting process any possible defects appearing in the cast are repaired with the application of welding techniques. The repaired cast should possess at least the same properties as the one which does not require any repairs. The aim of this thesis was to determine the impact of the heat treatment on the microstructure of the QE22 alloy welded joint. The creep resistance of the welded joints was also analyzed.


Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 915 ◽  
Author(s):  
Konat

The paper presents structure and mechanical properties of welded joints of the high-strength, abrasive-wear resistant steel Hardox Extreme. It was shown that, as a result of welding this steel, structures conducive to lowering its abrasion-wear resistance are created in the heat-affected zone. Width of the zone exceeds 60 mm, which results in accelerated wear in the planned applications. On the grounds of the carried-out examinations of structures and selected mechanical properties, a welding technology followed by heat treatment of heat-affected zones was suggested, leading to reconstruction of HAZ structures that is morphologically close to the base material structure. In spite of high carbon equivalent (CEV) of Hardox Extreme, the executed welding processes and heat treatment did not result in the appearance, in laboratory conditions, of welding imperfections in the welded joints.


2015 ◽  
Vol 229 ◽  
pp. 105-114 ◽  
Author(s):  
Agata Turowska ◽  
Janusz Adamiec

The WE43 cast magnesium alloy is characterized by high development prospects due to its strength properties and maximum operating temperature of up to 250°C. It is used in the automotive and aircraft industries for engine, hull and gear parts. These are mainly individual or low-volume large-size casts, which in the casting process may display some defects in the form of misruns, shrinkage porosities and cracks. These defects are repaired with the application of welding technologies, which are also used to joint castings into structures and to repair castings after operation. The weld joint is an integral part of the structure. Therefore, it decides on the properties of the entire structure. It is important to get to know the microstructure and properties of magnesium alloy weld joints, and in particular those of the fusion weld. In this paper stability of the structure of WE43 cast magnesium alloy welded joint was researched.


2013 ◽  
Vol 211 ◽  
pp. 77-82
Author(s):  
Izabela Pikos ◽  
Andrzej Kiełbus ◽  
Janusz Adamiec

The Elektron 21 is a commercial magnesium alloy containing Zn, Nd, Gd and Zr. The addition of rare earth elements improve its mechanical properties at elevated temperatures, what contribute to widen the range of applications. Constructions working at elevated temperatures can be exposed to its rapid changes. The purpose of present paper is to present results of study on reaction of Elektron 21 on applied thermal shock. As-cast material was heat treated according to four different variations. Afterwards, five cycles of thermal shocks, consisted of heating to 200°C (service temperature) and rapid cooling in water, have been applied. After heat treatment and each cycle of thermal shock the hardness and microstructure have been studied. The investigated material revealed satisfactory resistant to thermal shock, regardless of applied various heat treatment.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 539
Author(s):  
Gonçalo M. Gorito ◽  
Aida B. Moreira ◽  
Pedro Lacerda ◽  
Manuel F. Vieira ◽  
Laura M. M. Ribeiro

Cast Ni-Si-B alloys have the potential for high-temperature applications because of their high resistance to wear, impact, corrosion, and oxidation at elevated temperatures due to an appropriate balance of hard phases and austenite that ensures a good compromise between toughness and hardness. In this work, NiSi3B2 specimens, fabricated by the lost-wax casting process, were investigated. Given the complex multiphase cast microstructure, a differential scanning calorimeter (DSC-TGA) analysis was employed to characterize the reactions that occur during solidification and the resulting phases were characterized using scanning electron microscopy (SEM), with energy-dispersive microanalysis (EDS) and backscattered electron (BSE) image and X-ray diffraction (XRD). Due to the presence of hard phases, machining of the Ni-Si-B components can pose additional difficulties. Therefore, the conditions of the solution heat treatment, which might lead to the homogenization of the microstructure, consequently improving its machinability, were also investigated. The results of the heat-treated samples indicated that the dissolution of the eutectic constituent is accompanied by a significant decrease in the hardness (approximately 17%). It is important to emphasize that the solution heat treatments carried out reduced the hardness without affecting the percentage of borides, which will allow improving the machinability without adversely affecting the alloy performance in service.


2015 ◽  
Vol 651-653 ◽  
pp. 677-682 ◽  
Author(s):  
Anatoliy Popovich ◽  
Vadim Sufiiarov ◽  
Evgenii Borisov ◽  
Igor Polozov

The article presents results of a study of phase composition and microstructure of initial material and samples obtained by selective laser melting of titanium-based alloy, as well as samples after heat treatment. The effect of heat treatment on microstructure and mechanical properties of specimens was shown. It was studied mechanical behavior of manufactured specimens before and after heat treatment at room and elevated temperatures as well. The heat treatment allows obtaining sufficient mechanical properties of material at room and elevated temperatures such as increase in ductility of material. The fractography of samples showed that they feature ductile fracture with brittle elements.


2016 ◽  
Vol 677 ◽  
pp. 125-132 ◽  
Author(s):  
Yuchun Yuan ◽  
Aibin Ma ◽  
Xiaofan Gou ◽  
Jinghua Jiang ◽  
Godfred Arhin ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3430
Author(s):  
Grzegorz Golański ◽  
Jacek Słania ◽  
Marek Sroka ◽  
Paweł Wieczorek ◽  
Michał Urzynicok ◽  
...  

In addition to good high-temperature creep resistance and adequate heat resistance, steels for the power industry must have, among other things, good weldability. Weldability of such steels is one of the criteria determining whether or not the material is suitable for applications in the power industry. Therefore, when materials such as martensitic steel Thor 115 (T115) are introduced into the modern power industry, the quality and properties of welded joints must be assessed. The paper presents the results of metallographic and mechanical investigations of T115 martensitic steel welded joints. The analysis was carried out on joints welded with two filler metals: WCrMo91 (No. 1) and EPRI P87 (No. 2). The scope of the investigations included: microstructural investigations carried out using optical, scanning and transmission electron microscopy and mechanical testing, i.e., Vickers microhardness and hardness measurement, static tensile test and impact test. The macro- and microstructural investigations revealed correct structure of the weld, without welding imperfections. The microstructural investigations of joint No. 1 revealed a typical structure of this type of joint, i.e., the martensitic structure with numerous precipitates, while in joint No. 2, the so-called Nernst’s layers and δ-ferrite patches were observed in the weld fusion zone as well as the heat affected zone (HAZ). The mechanical properties of the test joints met the requirements for the base material. A slight influence of the δ-ferrite patch on the strength properties of joint No. 2 was observed, and its negative effect on the impact energy of HAZ was visible.


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