scholarly journals Airflow Dynamics and Aluminum Coating Oxidation Behavior under Electric-Arc Spraying with Airflow Pulsations

2021 ◽  
Vol 11 (18) ◽  
pp. 8444
Author(s):  
Irina Zakharova ◽  
Vyacheslav Royanov ◽  
Valeriy Chigarev
Keyword(s):  
Volume Fraction ◽  
Dynamic Structure ◽  
Electric Arc ◽  
Aluminum Coating ◽  
Arc Spraying ◽  
Metal Oxidation ◽  
Air Supply ◽  
Photo Visualization ◽  
Air Pulsation

The paper aims to investigate the airflow dynamics of electric-arc spraying (EAS) with airflow pulsation. The study is focused on the dynamic structure of the airflow with an obstacle in the form of crossed electrodes at the steady and the pulsating air supply (with a frequency up to 120 Hz). The work was fulfilled using a computer simulation, the airflow “shadow” photo visualization, and the microstructure characterization of the coatings formed. It was found that when air flows along the crossed electrodes with a gap of 2 mm, a depression zone appears in the flow with a pressure drop from 0.56 MPa to 0.01 MPa. The air pulsation resulted in a change in a flow’s dynamic structure towards an increase in the length of the depression zone, which covers most of the arc, affecting the liquid metal oxidation. It is established that the frequency of a droplet formation should match the frequency of the airflow pulsation to minimize the metal oxidation. With the air pulsating at about 65 Hz, the oxide volume fraction in the aluminum coating was reduced by 3.6 times compared to the steady airflow. EAS with airflow pulsation has the potential for technological cost reduction.

scholarly journals Characterization of spherical stainless steel powders prepared by electric arc spraying process

2020 ◽  
Vol 848 ◽  
pp. 012033
Author(s):  
A A Kirsankin ◽  
T A Kalaida ◽  
M A Kaplan ◽  
M A Smirnov ◽  
A Yu Ivannikov ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Electric Arc ◽  
Arc Spraying ◽  
Spraying Process

Influence of Process Parameters and Geometry of the Spraying Nozzle on the Properties of Titanium Deposits Obtained in Wire Arc Spraying

2015 ◽  
Vol 1111 ◽  
pp. 211-216
Author(s):  
Bogdan Florin Toma ◽  
Iulian Ionita ◽  
Diana Antonia Gheorghiu ◽  
Lucian Eva ◽  
Costică Bejinariu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Process Parameters ◽  
High Speed ◽  
Electrical Current ◽  
Electric Arc ◽  
Arc Spraying ◽  
Oxide Content ◽  
Spray Parameters ◽  
Influence Of Process Parameters ◽  
Wire Arc Spraying

Influence of the process parameters and geometry of the spraying nozzle on the properties of titanium deposits obtained in wire arc spraying. Wire arc spraying is a process in which through minor modifications of the spray parameters, they can have a major impact on the coatings properties. In this paper there is presented a study on the influence of process parameters and fluid dynamics of the atomization gas on the properties of titanium deposits (14T - 99.9% Ti). For this there were used three different frontal spraying nozzles, having different geometries, and were varied the spraying gas pressure and the electrical current on three levels. There were evaluated the particles velocity, coating density, chemical composition and characteristic interface between deposition and substrate. Obviously, the high speed of the atomization gas determinate the improving of all properties, but in the same time increased the oxide content in the layer. However, the oxidation can be drastically reduced if the melting and atomization of the wire droplets is produced at the point of formation of the electric arc, and the spraying jet is designed to constrain the electric arc. The assessment of deposits adherence allowed the observation of process parameters that contribute to its improvement.

Magnetic Characterization of SUS316L Deformed by High Pressure Torsion

2011 ◽  
Vol 239-242 ◽  
pp. 1300-1303
Author(s):  
Hong Cai Wang ◽  
Minoru Umemoto ◽  
Innocent Shuro ◽  
Yoshikazu Todaka ◽  
Ho Hung Kuo
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Stainless Steel ◽  
Phase Transformation ◽  
Austenitic Stainless Steel ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Austenitic Matrix ◽  
Magnetic Characterization

SUS316L austenitic stainless steel was subjected to severe plastic deformation (SPD) by the method of high pressure torsion (HPT). From a fully austenitic matrix (γ), HPT resulted in phase transformation from g®a¢. The largest volume fraction of 70% a¢ was obtained at 0.2 revolutions per minute (rpm) while was limited to 3% at 5rpm. Pre-straining of g by HPT at 5rpm decreases the volume fraction of a¢ obtained by HPT at 0.2rpm. By HPT at 5rpm, a¢®g reverse transformation was observed for a¢ produced by HPT at 0.2rpm.

A Novel Processing Route for the Fabrication of Monolithic and Composite Silicon Nitride

1992 ◽  
Vol 287 ◽  
Author(s):  
R. V. Raman ◽  
S. V. Rele
Keyword(s):  
Volume Fraction ◽  
Hot Isostatic Pressing ◽  
Thermal Exposure ◽  
Processing Route ◽  
Promising Alternative ◽  
Α Phase ◽  
Key Issues ◽  
Novel Processing ◽  
Composite Silicon

ABSTRACTCurrent hot isostatic consolidation methodology used for the fabrication of complex-shaped Si3N4-based components requires the use of an expensive glass encapsulation technique and extended thermal exposure (in hours) of the specimen. An alternative consolidation approach involving the use of solid pressure transmitting media under high pressure, has enabled the consolidation of Si3N4 alloys without the need for glass encapsulation.Characterization of microstructures and mechanical properties of this (MOR, fracture toughness) material has been carried out and will be presented. It has been noted that in Si 3N4/8%Y2O3-4%Al2O3 composition, consolidated using this approach, a significantly larger volume fraction of α phase has been retained compared with typically observed conversion in α⇒ β in hot isostatically pressed material or sintered material.Key issues for addressing densification and microstructure control using this process are presented. This rapid consolidation approach appears to be a promising alternative to hot isostatic pressing for the fabrication of complex-shaped Si3N4 components.

Estimation of Interlayer Thickness in Inorganic Particulate-Filled Polymer Composites

2011 ◽  
Vol 24 (6) ◽  
pp. 777-788 ◽  
Author(s):  
J.Z. Liang
Keyword(s):  
Polymer Composites ◽  
Volume Fraction ◽  
Particle Diameter ◽  
Interfacial Structure ◽  
Interlayer Thickness ◽  
Filled Polymer ◽  
Mechanical And Physical Properties ◽  
The Relationship ◽  
Good Agreement

The structure of the interlayer between matrix and inclusions affect directly the mechanical and physical properties of inorganic particulate-filled polymer composites. The interlayer thickness is an important parameter for characterization of the interfacial structure. The effects of the interlayer between the filler particles and matrix on the mechanical properties of polymer composites were analyzed in this article. On the basis of a simplified model of interlayer, an expression for estimating the interlayer thickness ([Formula: see text]) was proposed. In addition, the relationship between the [Formula: see text] and the particle size and its concentration was discussed. The results showed that the calculations of the [Formula: see text] and thickness/particle diameter ratio ([Formula: see text]) increased nonlinearly with an increase of the volume fraction of the inclusions. Moreover, the predictions of [Formula: see text] and the relevant data reported in literature were compared, and good agreement was found between them.

METALLURGICAL AND CORROSION CHARACTERIZATION OF POST WELD HEAT TREATED DUPLEX STAINLESS STEEL (UNS S31803) JOINTS BY FRICTION WELDING PROCESS

2016 ◽  
Vol 23 (03) ◽  
pp. 1650013 ◽  
Author(s):  
MOHAMMED ASIF M. ◽  
KULKARNI ANUP SHRIKRISHNA ◽  
P. SATHIYA
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Friction Welding ◽  
Volume Fraction ◽  
Welding Process ◽  
Equilibrium Temperature ◽  
Weld Interface ◽  
Heat Treated ◽  
Weld Heat

The present study focuses on the metallurgical and corrosion characterization of post weld heat treated duplex stainless steel joints. After friction welding, it was confirmed that there is an increase in ferrite content at weld interface due to dynamic recrystallization. This caused the weldments prone to pitting corrosion attack. Hence the post weld heat treatments were performed at three temperatures 1080[Formula: see text]C, 1150[Formula: see text]C and 1200[Formula: see text]C with 15[Formula: see text]min of aging time. This was followed by water and oil quenching. The volume fraction of ferrite to austenite ratio was balanced and highest pit nucleation resistance were achieved after PWHT at 1080[Formula: see text]C followed by water quench and at 1150[Formula: see text]C followed by oil quench. This had happened exactly at parameter set containing heating pressure (HP):40 heating time (HT):4 upsetting pressure (UP):80 upsetting time (UP):2 (experiment no. 5). Dual phase presence and absence of precipitates were conformed through TEM which follow Kurdjumov–Sachs relationship. PREN of ferrite was decreasing with increase in temperature and that of austenite increased. The equilibrium temperature for water quenching was around 1100[Formula: see text]C and that for oil quenching was around 1140[Formula: see text]C. The pit depths were found to be in the range of 100[Formula: see text]nm and width of 1.5–2[Formula: see text][Formula: see text]m.

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