scholarly journals Formation of Al-alloyed Layer on Magnesium with Use of Casting Techniques

2016 ◽  
Vol 16 (1) ◽  
pp. 112-116 ◽  
Author(s):  
R. Mola ◽  
T. Bucki ◽  
A. Dziadoń
Keyword(s):  
Solid Solution ◽  
Surface Layer ◽  
Casting Process ◽  
Outer Zone ◽  
Intermetallic Phases ◽  
Deep Penetration ◽  
Alloyed Layer ◽  
Molten Magnesium ◽  
Magnesium Melt ◽  
Steel Mould

Abstract Al-enriched layer was formed on a magnesium substrate with use of casting. The magnesium melt was cast into a steel mould with an aluminium insert placed inside. Different conditions of the casting process were applied. The reaction between the molten magnesium and the aluminium piece during casting led to the formation of an Al-enriched surface layer on the magnesium substrate. The thickness of the layer was dependent on the casting conditions. In all fabricated layers the following phases were detected: a solid solution of Mg in Al, Al3Mg2, Mg17Al12 and a solid solution of Mg in Al. When the temperature of the melt and the mould was lower (variant 1 – 670°C and 310°; variant 2 – 680°C and 310°C, respectively) the unreacted thin layer of aluminium was observed in the outer zone. Applying higher temperatures of the melt (685°C) and the mould (325°C) resulted in deep penetration of aluminium into the magnesium substrate. Areas enriched in aluminium were locally observed. The Al-enriched layers composed mainly of Mg-Al intermetallic phases have hardness from 187-256 HV0.1.

The Use of Trimethylaluminum for Producing Surface Layers by the PACVD Method

2005 ◽  
Vol 475-479 ◽  
pp. 3887-3890 ◽  
Author(s):  
Jerzy Robert Sobiecki ◽  
R. Sitek ◽  
Tadeusz Wierzchoń
Keyword(s):  
Surface Layer ◽  
Nickel Alloys ◽  
Argon Plasma ◽  
Outer Zone ◽  
High Heat ◽  
Intermetallic Phases ◽  
Point Of View ◽  
Aluminum Oxynitride ◽  
High Heat Resistance ◽  
Surface Layers

The paper presents the use of trimethylaluminum in PACVD method to obtain the surface layers like alumina or aluminum nitride on Inconel nickel alloy. The glow discharge nitriding at a temperature of 750°C leads to the formation of aluminum oxynitride in the layer, whereas annealing in argon plasma at a temperature of 1050°C – to the formation of nickel and aluminum based intermetallic phases of the NiAl or Ni3Al type with aluminum oxide present within the outer zone of the coating. The presence of the surface layer of the Al2O3+NiAl+Ni3Al type formed on nickel alloys may be significant from the point of view of the applications that require a high heat resistance.

Changes in Residual Stress in Worked Surface Layer of Type 304 Austenitic Stainless Steel Due to Tensile Deformation

2000 ◽  
Vol 123 (1) ◽  
pp. 130-134
Author(s):  
Makoto Hayashi ◽  
Kunio Enomoto
Keyword(s):  
Solid Solution ◽  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Residual Stresses ◽  
Tensile Deformation ◽  
End Mill ◽  
Heat Treated ◽  
304 Austenitic Stainless Steel ◽  
Type 304

Changes in the residual stress in a worked surface layer of type 304 austenitic stainless steel due to tensile deformation were measured by the X-ray diffraction residual stress measuring method. The compressive residual stresses introduced by end-mill, end-mill side cutter, and grinder were easily changed into tensile stresses when the plate specimens were subjected to tensile stress greater than the yield stress of the solid solution heat-treated material. The residual stresses after the tensile deformation depend on the initial residual stresses and the degree of preliminary working. The behavior of the residual stress changes can be interpreted if the surface-worked material is regarded as a composite made of solid solution heat-treated material and work-hardened material.

Effect of Annealing Treatment on the Structure and Microhardness of Cold-Sprayed Nanostructured FeAl/WC Composite Coating

2008 ◽  
Vol 373-374 ◽  
pp. 73-76 ◽  
Author(s):  
Hong Tao Wang ◽  
Guan Jun Yang ◽  
Chang Jiu Li ◽  
Cheng Xing Li
Keyword(s):  
Solid Solution ◽  
Annealing Time ◽  
Composite Coatings ◽  
Annealing Treatment ◽  
Nanocrystalline Structure ◽  
Intermetallic Phases ◽  
Coating Structure ◽  
Intermetallic Composite ◽  
Sprayed Coating ◽  
Sprayed Coatings

Nanostructured FeAl/WC intermetallic composite coatings were prepared by cold spaying of the ball-milled powders. The effect of annealing on the coating structure and microhardness was examined. It was found that the nanocrystalline structure of the milled feedstock was retained in the cold sprayed coatings. The FeAl intermetallic phases were formed from the milled Fe(Al) solid solution during the post-spraying annealing at 550oC. The microhardness of the as-sprayed coating was about 680HV0.1 and it decreased a little with increasing the annealing time at 550oC.

The Intermetallic Phases in Sand Casting Magnesium Alloys for Elevated Temperature

2011 ◽  
Vol 690 ◽  
pp. 214-217 ◽  
Author(s):  
Andrzej Kiełbus ◽  
Tomasz Rzychoń
Keyword(s):  
Solid Solution ◽  
Elevated Temperature ◽  
Grain Boundaries ◽  
Magnesium Alloys ◽  
Solution Structure ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Phase Identification ◽  
Al Alloy ◽  
Cast Microstructure

In the present article, the phase identification of four magnesium alloys: Mg-9wt%Al, Mg-8wt%Al-2wt%Ca-0.5wt%Sr, Mg-5wt%Y-4wt%RE and Mg-3wt%Nd-1wt%Gd were studied. The results showed that Mg-9wt%Al alloy contains only the Mg17Al12 intermetallic phase in α-Mg matrix. As-cast microstructure of Mg-8wt%Al-2wt%Ca-0.5wt%Sr alloy consist of α-Mg matrix with (Al,Mg)2Ca and (Al,Mg)4Sr phases. The Mg-5wt%Y-4wt%RE alloy showed several phases. This alloy was characterized by a solid solution structure α-Mg with eutectic α-Mg + Mg14Y2Nd on grain boundaries. The precipitates of MgY, Mg2Y, Mg24Y5 phases have been also observed. The Mg-3wt%Nd-1wt%Gd alloy composed mainly of a solid solution structure α-Mg with eutectic α-Mg + Mg3(Nd,Gd) on the grain boundaries. The regular precipitates of MgGd3 phase have been also observed.

THE INFLUENCE OF ADDITIVE TECHNOLOGY ON THE QUALITY OF THE SURFACE LAYER AND THE STRENGTH STRUCTURE OF PROSTHETIC CROWNS

Tribologia ◽  
2018 ◽  
Vol 280 (4) ◽  
pp. 13-22
Author(s):  
Łukasz BOJKO ◽  
Wojciech RYNIEWICZ ◽  
Anna M. RYNIEWICZ ◽  
Marcin KOT ◽  
Paweł PAŁKA
Keyword(s):  
Surface Layer ◽  
Layer Structure ◽  
Casting Process ◽  
Additive Technology ◽  
Cocrmo Alloy ◽  
Casting Technology ◽  
Stomatognathic System ◽  
Cad Cam ◽  
Hard Structures

Prosthetic crowns reproduce the damaged hard structures of the patient’s own teeth and take over their natural functions, thus securing the correct reconstruction of the stomatognathic system. The aim is to evaluate the crowns for premolars and molars produced by casting, milling, and Selective Laser Melting technologies, in terms of the accuracy of reproducing the degree against the prosthetic pillar, the analysis of the surface layer structure of the step, and the micromechanical parameters of the alloy. The study material included CoCrMo alloy crowns. The conducted study allowed finding that the tightness of prosthetic crowns made using traditional casting technology as well as in SLM milling and technology is comparable and meets clinical requirements. Structural crown analyses confirmed the very good quality of the surface layer obtained with milling technology and SLM technology using the CAD/CAM method. SLM and digital milling allow the formation of precise and durable structures constituting the foundation of crowns in a time much shorter than the casting process.

scholarly journals Microstructure of the Bonding Zone Between AZ91 and AlSi17 Formed by Compound Casting

2017 ◽  
Vol 17 (1) ◽  
pp. 202-206 ◽  
Author(s):  
R. Mola ◽  
T. Bucki ◽  
A. Dziadoń
Keyword(s):  
Intermetallic Phase ◽  
Casting Process ◽  
Az91 Alloy ◽  
Atmospheric Conditions ◽  
Az91 Magnesium Alloy ◽  
Compound Casting ◽  
Az91 Magnesium ◽  
Alloy Microstructure ◽  
Bonding Zone ◽  
Steel Mould

AbstractThis paper discusses the joining of AZ91 magnesium alloy with AlSi17 aluminium alloy by compound casting. Molten AZ91 was cast at 650°C onto a solid AlSi17 insert placed in a steel mould under normal atmospheric conditions. Before casting, the mould with the insert inside was heated up to about 370°C. The bonding zone forming between the two alloys because of diffusion had a multiphase structure and a thickness of about 200 μm. The microstructure and composition of the bonding zone were analysed using optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The results indicate that the bonding zone adjacent to the AlSi17 alloy was composed of an Al3Mg2intermetallic phase with not fully consumed primary Si particles, surrounded by a rim of an Mg2Si intermetallic phase and fine Mg2Si particles. The bonding zone near the AZ91 alloy was composed of a eutectic (an Mg17Al12intermetallic phase and a solid solution of Al and Si in Mg). It was also found that the compound casting process slightly affected the AZ91 alloy microstructure; a thin layer adjacent to the bonding zone of the alloy was enriched with aluminium.

Effect of Fe on microstructures and mechanical properties of an Al–Mg–Si–Cu–Cr–Zr alloy prepared by low frequency electromagnetic casting

2017 ◽  
Vol 32 (11) ◽  
pp. 2067-2078
Author(s):  
Yi Meng ◽  
Jian-zhong Cui ◽  
Zhi-hao Zhao
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Low Frequency ◽  
Hot Extrusion ◽  
Casting Process ◽  
Electromagnetic Casting ◽  
Fe Content ◽  
Microstructures And Mechanical Properties ◽  
Phase Q ◽  
Zr Alloy

The effects of different Fe contents (0.168, 0.356 and 0.601 wt%) on microstructures and mechanical properties of the Al–1.6Mg–1.2Si–1.1Cu–0.15Cr–0.15Zr (all in wt%) alloys prepared by low frequency electromagnetic casting process were investigated in the process of solidification, hot extrusion, solid solution and aging treatments. The results show that the increase of Fe content promotes the formation of feathery grains in the process of solidification and the precipitation of another important strengthening phase Q′ with small size. Additionally, it also results in no recrystallization even after solid solution at a high temperature of 550 °C, which is because of the increase number of elliptical shaped and fine DO22-Al3Zr dispersoids (∼70 nm long and ∼35 nm wide) and the spherical or elliptical shaped Fe-containing phases. When Fe content of the alloy increases to 0.356 wt%, both the ultimate tensile strength and yield strength of the alloy-T6 increase by more than 60 MPa and with little cost of ductility.

Iron Phases in Model Al-Mg-Si-Cu Alloys

2011 ◽  
Vol 674 ◽  
pp. 135-140 ◽  
Author(s):  
Marzena Lech-Grega ◽  
Sonia Boczkal
Keyword(s):  
Solid Solution ◽  
Intermetallic Phases ◽  
Silicon Iron ◽  
Cu Alloys ◽  
Quantitative Content ◽  
Different Content ◽  
6Xxx Series ◽  
Small Content ◽  
Cast Condition ◽  
Iron Precipitates

Iron phases present in alloys from the 6xxx series affect the workability behaviour of these alloys. Iron in these alloys occurs in the form of intermetallic phases and AlFe, α-AlFeSi, β- AlFeSi eutectics. The homogenisation treatment is carried out to induce the transformation of  phase into phase The aim of the studies was EDX and EBSD analysis by scanning microscopy of iron phases present in model alloys based on 6061 system, characterised by the silicon-iron ratio Si/Fe=0,5 and 1, examined in as-cast condition and after homogenisation, followed by a comparison of the detected phases with phases present in industrial ingots. In 6061 alloy, copper in the amount of 0,4wt.% occurred in the solid solution of aluminium. The EDX analysis proved that copper atoms were embedded also in iron precipitates, and scarce phases of an AlxCuy type were being formed. Different content of magnesium in the examined alloys (0,8 and 1,2wt.%) affected not only the quantitative content of Mg2Si phases, but also the presence of AlFe phases in alloy with small content of Si (0,4wt.%) and high content of Mg (1,2wt.%).

Weldability of the MSRB Magnesium Alloy

2011 ◽  
Vol 176 ◽  
pp. 107-118 ◽  
Author(s):  
Janusz Adamiec
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Magnesium Alloy ◽  
Intermetallic Phases ◽  
Structural Constituent ◽  
Temperature Range ◽  
Partial Tears ◽  
Recovery Temperature

This work, in combination with industrial tests of casting welding, shows that the causes of high-temperature brittleness are the partial tears of the structure and the hot cracks of both the castings, as well as the welded and padded joints. Such phenomena should be treated as irreversible failures caused by the process of crystallization that is in the area of co-existence of the solid and liquid structural constituent. Nil-strength temperature (NST), nil-ductility temperature (NDT) and ductility recovery temperature (DRT) were determined using Gleeble 3800. Obtained results enabled the defining of brittle temperature range of MSR-B magnesium alloy. The assessment of the resistance to hot fractures was conducted on the basis of the transvarestriant trial. The transvarestriant trial involves changing of strain during welding. It was stated that the range of the high-temperature brittleness is very broad, which significantly limits the application of the welding techniques to join or repair elements made of the MSRB alloy. brittleness is caused mainly by metallurgical factors, i.e. precipitation of intermetallic phases from the solid solution.

Protective System for Magnesium Melt

2005 ◽  
Vol 488-489 ◽  
pp. 85-88 ◽  
Author(s):  
A. Karger ◽  
Friedrich Wilhelm Bach ◽  
C. Pelz
Keyword(s):  
The Other ◽  
Protective Atmosphere ◽  
Ministry Of Education ◽  
Molten Bath ◽  
New Methods ◽  
Environmental Friendly ◽  
Protective System ◽  
Molten Magnesium ◽  
Magnesium Melt ◽  
Gas Expansion

The environmentally friendly alternatives are being examined by an R&D group funded by German Federal Ministry of Education and Research. The research goals of this group are to analyze the potential of known environmental friendly gases to serve as protective atmosphere, and also to develop and to evaluate new methods for protecting the surface of magnesium melts. One possible alternative is covering the magnesium melt with CO2-snow, which is deposited on the molten bath and decreases the surface temperature of the melt. On the other hand gas expansion is the result of the sublimation of the CO2-snow which displaces any oxygen at the surface of the molten magnesium.

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