scholarly journals The Effect of Nanometric α-Al2O3 Addition on Structure and Mechanical Properties of Feal Alloys Fabricated by Lens Technique

2017 ◽  
Vol 62 (3) ◽  
pp. 1703-1712 ◽  
Author(s):  
M. Łazińska ◽  
T. Durejko ◽  
W. Polkowski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Intermetallic Alloy ◽  
First Principle ◽  
Metal Pool ◽  
Structure And Properties ◽  
Indirect Methods ◽  
Α Al2o3 ◽  
Melted Metal

AbstractResults of the first principle study on a fabrication of FeAl intermetallic based alloy with an addition of nanometric αAl2O3(n-Al2O3) particles by the LENS method and a subsequent characterization of the as received materials’ structure and properties, are shown in the present work. A series of samples were manufactured using LENS technique while a control of temperature and the size of melted metal pool. The presence of ceramics nanoparticles was not directly confirmed by microscopy observations. Neither aluminum nor oxygen content was not elevated in the material with n-Al2O3content. Although, indirect methods revealed influence of n-Al2O3addition on the manufactured elements structure. Analyses of porosity has shown that addition of 2% vol. n-Al2O3significantly decreases this feature (~1%), as compared to the reference material made of pure FeAl intermetallic alloy (~5%). The addition of n-Al2O3causes an increase of grain size in Fe40Al intermetallic alloy. An oxidation resistance has been also improved what was associated to the n-Al2O3addition. Four times lower increase of samples mass was noticed for sample with the n-Al2O3addition as compared to the pure Fe40Al intermetallic alloy.

Characterization of Fusion Lines Obtained with Laser Welding on Ductile Iron Plates

2016 ◽  
Vol 254 ◽  
pp. 33-42
Author(s):  
Ioan Catalin Mon ◽  
Mircea Horia Tierean ◽  
Eugen Cicala ◽  
Michel Pilloz ◽  
Iryna Tomashchuk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Laser Welding ◽  
Welding Speed ◽  
Ductile Iron ◽  
Continuous Laser ◽  
Welding Defects ◽  
Criteria For Selection ◽  
Selection Of ◽  
Melted Metal

This paper studies the ductile iron (DI) weldability using laser welding. For performing an Yb:YAG continuous laser was used, with a maximum power of 6 kW. The parametrical window power (P) - welding speed (S) was explored by carrying out the fusion lines on ductile iron plates without preheating, to determinate areas of weldability (complete penetration, correct geometry) to allow further characterization. The criteria for selection of focus areas were the geometry of the fusion lines and the absence of the welding defects. The unsatisfactory domains were characterized by: collapse of the melted metal, incomplete penetration, low fusion lines quality (geometry, compactness). In present study, several values of power and welding speed have been tested to identify their influence on geometry, compactness of the joints and mechanical properties. As result, the power-welding speed diagram for feasible domains of laser welding was generated.

Effect of Thermomechanical Processing on Grain Size, Texture and Mechanical Properties of Pure Magnesium

2020 ◽  
Vol 985 ◽  
pp. 97-108
Author(s):  
Mouhamadou Moustapha Sarr ◽  
Motohiro Yuasa ◽  
Hiroyuki Miyamoto
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Stress ◽  
Thermomechanical Processing ◽  
Pure Magnesium ◽  
Grain Structure ◽  
Misorientation Distribution ◽  
Processed Material ◽  
Texture Characterization

This study aims to investigate the effect of processing routes (A and Bc) and temperature on microstructure, texture and mechanical properties of pure magnesium was studied in this research. An extruded pure magnesium (~99,9 %) was subjected to severe plastic deformation (SPD) by ECAP. Deformation was conducted at 523K and 473K and two different processing routes (A and Bc) were used to control the texture. The microstructure and texture characterization of the pressed materials were carried out. It was found that the microstructure displayed a bimodal grain structure after two passes and then became homogeneous after four passes following both routes A and Bc. The misorientation distribution was examined and the results revealed that the fraction of high angle grain boundaries (HAGB) was higher at temperature 473K. The texture was randomized following route Bc whereas it became strengthened in route A after four passes. According to the Hall-Petch (HP) relationship, the yield stress of polycrystalline metals increases with a decrease in grain size. In this study, a positive slope k was achieved in the strengthened texture while a negative one was obtained in the softened texture. The ductility of ECAP processed material was considerably improved (from 23% to 38%) without sacrificing the yield stress by route Bc at 423K.

scholarly journals THE INFLUENCE OF MECHANICALLY ALLOYED MODIFYING MASTER LIGATURES ON STRUCTURE AND PROPERTIES OF WELDED JOINTS

2018 ◽  
pp. 102-108
Author(s):  
F. G. Lovshenko ◽  
G. F. Lovshenko ◽  
A. I. Khabibulin
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Weld Metal ◽  
Welded Joints ◽  
Dispersion Hardening ◽  
Structure And Properties ◽  
Mechanically Alloyed ◽  
Actual Problem ◽  
Effective Technology

Actual problem of modern welding production is the creation of electrodes for maximum performance and efficiency of the process whithin the required reliability and durability of the structure. A promising way to improve mechanical properties of the weld metal is the implementation of the mechanism of dispersion hardening. Reactionary mechanical alloying is an effective technology of obtaining nanocrystalline modifying ligatures and modifiers. The use of electrodes with an experimental coating containing a mechanically alloyed, composite ligature to resolve transcrystalline type of structure of the weld metal and reduce the grain size by 2.5–3.0 times (from # 8–9 to #11–12) reduces by 20–30% the threshold of cold brittleness and increase by 15– 25% of the mechanical properties of the weld metal.

scholarly journals Generation, structure and properties of the modified welding seams

2018 ◽  
pp. 131-140
Author(s):  
F. G. Lovshenko ◽  
A. I. Khabibulin
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Weld Metal ◽  
Cold Brittleness ◽  
Structure And Properties ◽  
Mechanically Alloyed ◽  
Aluminum Oxides ◽  
Generation Structure ◽  
Effective Technology

Preparation, structure and properties of modified welds by using electrodes with coatings, which contain, along with classical components, a modifying ligature. The ligature is mechanically and thermally synthesized composite submicrocrystalline powders with nanosized inclusions of aluminum oxides. Reactionary mechanical alloying is an effective technology of obtaining nanocrystalline modifying ligatures and modifiers. The use of electrodes with an experimental coating containing a mechanically alloyed, composite ligature to resolve transcrystalline type of structure of the weld metal and reduce the grain size by 2,5–3,0 times (from № 8–9 to № 11–12) reduces by 20–30% the threshold of cold brittleness and increase by 15–25% of mechanical properties of the weld metal.

Effects of Repeated Plastic Working (RPW) Process on the Structure and Properties of Mg2Si/Mg-Zn-Er Composite

2010 ◽  
Vol 146-147 ◽  
pp. 1222-1226
Author(s):  
Shu Bo Li ◽  
Ya Ling Qin ◽  
Han Li ◽  
Wen Bo Du
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Ultimate Strength ◽  
Matrix Alloy ◽  
Structure And Properties ◽  
Plastic Working ◽  
Magnesium Matrix ◽  
The Matrix ◽  
Silicon Particles

The Mg matrix composite (Mg2Si/Mg-5Zn-2.5Er) was prepared using repeated plastic working (RPW) technique. and the effects of the number of RPW cycles on the microstructure and mechanical properties of these composites were investigated. The results indicated that the added silicon particles fully reacted with the magnesium matrix, and theMg2Si/Mg-5Zn-2.5Er composites were successfully achieved. When the number of RPW cycle increased, the size of the Mg2Si particles decreased, and the grain size of the matrix alloy reached the minimum when 200 RPW cycles was used. The best mechanical properties were also identified as 394 MPa ultimate strength, and 363 MPa yield strength, when 200 RPW cycles were used.

Preparation and Characterization of Alumina/TZP Particulate Composites

2007 ◽  
Vol 29-30 ◽  
pp. 259-262
Author(s):  
Y. Ki Cho ◽  
Tae Young Yang ◽  
Jae Myung Lee ◽  
Seog Young Yoon ◽  
Hong Chae Park
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Grain Size ◽  
Particulate Composites ◽  
Major Phase ◽  
Microstructure And Mechanical Properties ◽  
Phase Type ◽  
Main Factors

Particulate composites prepared by sintering compacts of Al2O3 and TZP powders, in air at 1500 and 1600 oC have been characterized in terms of microstructure and mechanical properties. The mechanical properties of the composites appear to be controlled by three main factors: the grain size of major phase, type of intergranular TZP, and presence of residual stress.

The Influence of Pulsed Heat and Power Supply on the Structure and Properties of Welded Joint Metals and Surfaced Coatings

2015 ◽  
Vol 788 ◽  
pp. 259-266
Author(s):  
Yuriy N. Saraev ◽  
Valeriy P. Bezborodov ◽  
Evgenya A. Putilova
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Weld Metal ◽  
Power Supply ◽  
Welded Joints ◽  
Arc Welding ◽  
Structural Changes ◽  
Welded Joint ◽  
Structure And Properties ◽  
Pulsed Mode

We have investigated the influence of the modes of adaptive pulse-arc welding and surfacing on the structure and physical-mechanical properties of welded joints of steel 09Mn2Si and the surfaced composition of this steel coated with a modified powder material of chromium carbide with the submicrocrystalline structure. It is shown that the pulsed mode of welding and surfacing can improve the homogeneity of the structure of the welded joint of steel and a surfaced coating and reduce the grain size of metals in both of them. Structural changes lead to an increase in ductility and toughness of the weld metal.

Cryomilling and Characterization of Ti/Al2O3 Powders

2018 ◽  
Vol 281 ◽  
pp. 285-290
Author(s):  
Jun Yan Wu ◽  
Qian Liu ◽  
Zhi Hao Wang ◽  
Zhi Wang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Grain Size ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Particle Size Analyzer ◽  
Distribution Phase ◽  
Xrd And Tem ◽  
Milled Powders

In order to prevent the oxidation of Ti, which ultimately leads to the generation of intermetallic compound Ti3Al, a new method of cryomill in liquid nitrogen was used to deal with the Ti/Al2O3 powders. The size distribution, phase composite and microstructure of the powders were analyzed using laser particle size analyzer, XRD, and TEM, respectively. Then, the performances of Ti/Al2O3 cermet sintered using cryomilled powders and room temperature milled powders were compared. The results show that, with the increase of cryomilling time, the grain size decreases shapely and high reactivitive nanoscale powders are finally obtained. With the cryomilling in liquid nitrogen, the Ti-N bonds are formed, which successfully prevent the oxidation of Ti. Ti/Al2O3 cermet sintered using cryomilled powders shows higher density, better mechanical properties than that using RT milled powders.

Study of structure, phase composition and physicomechanical properties of modified castings from heat-temperature ZhS3DK alloy

2021 ◽  
pp. 122-131
Author(s):  
V.N. Gadalov ◽  
V.R. Petrenko ◽  
E.A. Filatov ◽  
I.V. Vornacheva ◽  
V.E. Dedenko
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Analysis ◽  
Grain Size ◽  
Physicomechanical Properties ◽  
Titanium Carbonitride ◽  
Structure And Properties ◽  
Critical Temperatures ◽  
Heat Temperature ◽  
Structure Phase

A study of the structure and properties of castings made with the use of various modifiers has been carried out. It was found that when the alloys are modified with titanium carbonitride and all used modifiers except tungsten carbide, the grain size decreases, and carbide precipitates are evenly distributed, contributing to an increase in mechanical properties. Using the method of differential thermal analysis, the critical temperatures at which phase transformations occur in the cast ZhS3DK alloy and its analogs with modifiers have been established. The modes of heat treatment of modified cast heat-resistant alloys of the ZhS3DK type have been specified.

Mechanical and Microstructural Characterization of Heat-Affected Zone Materials of Reactor Pressure Vessel

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Jinya Katsuyama ◽  
Tohru Tobita ◽  
Yutaka Nishiyama ◽  
Kunio Onizawa
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Pressure Vessel ◽  
Postweld Heat Treatment ◽  
Microstructural Characterization ◽  
Reactor Pressure Vessel ◽  
Reactor Pressure

In order to provide the technical basis for the judgment of the needs of surveillance specimens of heat-affected zone (HAZ) in reactor pressure vessel (RPV) steels, we performed a research on the characterization of metallurgical and mechanical properties of the HAZ in RPV steels. The distributions of grain size and phases were drawn as a map based on temperature histories around HAZ obtained from welding simulation. Referring to the HAZ map, typical HAZ materials were made by simulating temperature histories including postweld heat treatment (PWHT) within the HAZ. Metallurgical and mechanical characteristics for those HAZ materials were compared with those of base metal. From the results, it is clear that mechanical properties of HAZ materials depend not on the prior austenitic grain size but mostly on the phases. Concerning on the fracture toughness in HAZ, HAZ materials close to weld metal indicated higher toughness than that of base metal due to mixed structure of martensite and lower-bainite, while HAZ materials close to base metal were equivalent or slightly lower toughness than that of base metal due to the same phase as base metal of upper-bainite.

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