scholarly journals Creation of AlSi12 Alloy Coating by Centrifugal Induction Surfacing with the Addition of Low-Melting Metals

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3555
Author(s):  
Aleksander I. Komarov ◽  
Lesław Kyzioł ◽  
Dmitry V. Orda ◽  
Donata O. Iskandarova ◽  
Igor A. Sosnovskiy ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Dendritic Structure ◽  
Alloy Coating ◽  
Centrifugal Forces ◽  
Aluminum Layer ◽  
Structural Formation ◽  
Main Layer ◽  
Interdendritic Space ◽  
Steel Base ◽  
Processing Cycle

This paper investigates the structure and mechanical characteristics of a coating based on an AlSi12 alloy, obtained by centrifugal induction surfacing as an alternative to a bronze sliding bearing. To provide for the adhesion of an aluminum layer to the inner surface of a steel bearing housing, a sublayer of low-melting metals was formed, while the formation of the main layer and the sublayer was done in a single processing cycle. The low-melting metals had higher density, which ensured that the sublayer was created at the interface with the steel bearing housing under the action of centrifugal forces. It is shown that the low-melting sublayer forms a strong bond both with the aluminum alloy and with the steel base. Lead and tin are used as low-melting additives. It has been established that lead or tin used in a sublayer are indirectly involved in the structural formation of boundary layers of steel and aluminum claddings, acting as a medium for diffuse mass transfer. Thus, lead is not included in the composition of the main coating and does not change the chemical composition of the aluminum layer. After the addition of tin, the aluminum develops a dendritic structure, with tin captured in the interdendritic space. In this case, the deposited layer is saturated with iron with the formation of intermetallic (Fe, Al, Si) compounds, both at the interface and in the coating volume. This paper offers an explanation of the mechanism through which Pb and Sn act on the structure formation of the coating, and on the boundary layer of the steel bearing housing. Tribological tests have shown that the resulting materials are a promising option for plain bearings and highly competitive with the CuSn10P bronze.

scholarly journals Structural and mechanical characteristics of some lead-free Cu-Sn based solder alloys

2008 ◽  
Vol 62 (3) ◽  
pp. 160-163 ◽  
Author(s):  
Aleksandra Mitovski ◽  
Ljubisa Balanovic ◽  
Dragana Zivkovic ◽  
Sasa Marjanovic ◽  
Bata Marjanovic ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Dendritic Structure ◽  
Production Method ◽  
Experimental Results ◽  
Lead Free ◽  
Solder Alloys ◽  
Slow Cooling ◽  
Mechanical And Electrical Properties ◽  
Additional Thermal Treatment ◽  
Lead Free Solders

The results of structural and mechanical characteristics of lead-free Cu-Sn based solder alloys, produced in Company "11. mart" AD Srebrenica (Republic of Srpska), are presented in this paper. The results of investigation of samples - alloys CuSnl4, CuSnlFelAlO.5, CuSnlOFelAllMnO.5 and CuA110Fe3Mn produced by different processing methods, include the data obtained by optical microscopy and measurements of hardness, micro hardness and electroconductivity, in order to characterize mentioned alloys and define the influence of processing method applied on their structural and mechanical properties. Microstructural experimental results of samples produced by casting in a metal mould with fast water cooling showed clearly sharp dendritic structure. Samples obtained by casting in a sand mould, displayed structure with big crystals, higher amount of segregation and inclusions on the grain boundaries, as a result of the slow cooling process. Hardness and microhardness tests showed increasing values as the amount of tin raised. Sample 3 showed the lowest value, as a result of the crystallization process and lackness of additional thermal treatment. Experimental results of the electroconductivity test showed that mentioned sample has got the highest value, which can be also explained by its production method. Results presented in this paper can contribute to investigations of copper-tin lead-free alloys, having in mind that various potential lead-free solders still haven't been completely investigated from the aspects of their structural, mechanical and electrical properties.

Study of Fe-Ni(Cr) Alloy and Nano-Al2O3 Particles Composite Coating Prepared by Laser Cladding

2006 ◽  
Vol 118 ◽  
pp. 585-590 ◽  
Author(s):  
Yeo Jian Hua ◽  
Zhang Wei ◽  
Gao Ming Xia ◽  
Zhang Qun Li
Keyword(s):  
Composite Coating ◽  
Laser Cladding ◽  
Mechanical Characteristics ◽  
Dendritic Structure ◽  
Processing System ◽  
Wear Property ◽  
Chromium Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Nickel

The experiments of laser cladding Ni-coated nano-Al2O3 powder were made on 2Cr13 stainless steel using 7kW CO2 laser processing system. The microstructure and mechanical characteristics of composite coating were tested by scanning electronic microscope (SEM), X-ray diffraction (XRD), energy dispersion analyzer of X-ray (EDAX) and microhardness tester. The results showed that the composite coating was composed of superfine cellular dendritic structure. The X-ray diffraction data revealed that the cellular grains were composed of nano-Al2O3 particles, iron nickel alloy and iron chromium alloy. The mechanical characteristics of composite coating greatly increased. Compared with parent metal, the average hardness of composite coating increased by 1 time, and its wear property increased by 1.25 times.

Segment Formation in the Work Pieces of ZA22 Grain Refined by Some Rare Earth Elements and Subjected to Equal Channel Angular Pressing, ECAP, Process

2017 ◽  
Vol 886 ◽  
pp. 74-78
Author(s):  
Adnan I.O. Zaid
Keyword(s):  
Mechanical Characteristics ◽  
Dendritic Structure ◽  
Weight Ratio ◽  
High Strength ◽  
Low Energy ◽  
Serrated Chip ◽  
Angular Pressing ◽  
Ecap Process ◽  
Chip Type ◽  
Wear And Corrosion

Zinc aluminum alloys in general and ZA22 in particular are versatile materials which are widely used in the automobile, aircraft and space craft industries due to their required and attractive properties e.g. high strength-to weight-ratio, good cast ability, high wear and corrosion resistances, in addition to the advantages of low–energy and non-polluting melting. . However, against these attractive properties they have the disadvantage of forming a dendritic structure with large grain size during solidification or homogenization of their casts, which tends to reduce their surface quality, mechanical and impact strengths. Hence it is very essential to modify their structure and refine their grains. In this paper, the effect of the ECAP process on ZA22 alloy after grain refinement of its structure by titanium, titanium plus boron and molybdenum on its metallurgical and mechanical characteristics is investigated. During the investigation, a new phenomenon had occurred on the upper surface of the work pieces, (the surface in contact with the upper part of the ECAP die) similar to the serrated chip type which was first observed by Merchant in1948, This formed the main objective of this paper, in which the causes of this new phenomenon, the mechanism of its formation and how to avoid its occurrence are presented and discussed.

scholarly journals The influence of morphology and crystal orientation of spangles on hot-dip Zn-0.5Sn alloy coating

2021 ◽  
Vol 57 (1) ◽  
pp. 63-72
Author(s):  
L. Zhai ◽  
H Peng ◽  
Y. Liu ◽  
Y. Lei ◽  
S. Deng ◽  
...  
Keyword(s):  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Energy Dispersive Spectrometer ◽  
Alloy Coating ◽  
Eutectic Structure ◽  
Element Distribution ◽  
Base Surface ◽  
Steel Base ◽  
Typical Morphology ◽  
Backscatter Diffraction

The study on the surface morphology and crystal orientation of the Zn-0.5Sn coating could offer some guidance to improve the surface performance of the hot-dip galvanizing coating. In this paper, a scanning electron microscope (SEM) and an energy dispersive spectrometer (EDS) were used to analyze the typical morphology and the element distribution of spangles. The surface texture of the coating was analyzed by X-ray diffraction (XRD). Electron backscatter diffraction (EBSD) was used to analyze the crystal orientation of spangles. The results show that Sn segregates among the spangle dendrites while a metastable divorced eutectic structure can be maintained in the tin-rich phase, where the composition tends to be very similar. The crystal orientation of spangles affects their morphology, leading to the formation of feathery, ridged, and orthogonal dendrite arm spangles. When the angle among the <0001> orientation of the spangle crystal and the normal of the steel base surface changes from 0? to 90?, feathery spangles change to orthogonal dendrite arms spangles. The misorientation within a spangle is small while that among spangles is quite large. The orientation changes in the direction of the dendrite arm are relatively smooth and low, while the orientation changes which are perpendicular to the dendrite arm have a saltatory and irregular fluctuation.

Research on the Mechanical Properties of a New “I” Type Double-Decker Ball Bearing

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Yili Zhu ◽  
Yongchun Zhang ◽  
Chaowu Jin
Keyword(s):  
Mechanical Model ◽  
Mechanical Characteristics ◽  
Ball Bearing ◽  
Calculation Model ◽  
Load Test ◽  
Centrifugal Forces ◽  
Test Rig ◽  
Double Decker ◽  
Bearing Load ◽  
Simulation Results

The new “I” type double-decker ball bearing (NITDDBB) with two inner contact ball bearings is proposed to improve the speed and load capability of the original I type double-decker ball bearing (OITDDBB). Based on the quasi-statics principle, the mechanical model of the NITDDBB is established and takes into consideration the radial load, axial load, and ball centrifugal forces, as well as the gyroscopic moments. The corresponding calculation model is established on the matlab platform. The mechanical characteristics of the NITDDBB are analyzed and compared with the OITDDBB and also with a single-decker ball bearing (SDBB). Finally, a bearing load test rig is designed and built to verify the simulation results. The results provide a theoretical and experimental basis for the application of the NITDDBB.

scholarly journals On the Bonding Strength of Fe-Based Self-Fluxing Alloy Coating Deposited by Different Methods on the Steel Substrate

2018 ◽  
Vol 23 (2) ◽  
pp. 355-364
Author(s):  
E. Feldshtein ◽  
M. Kardapolava ◽  
O. Dyachenko
Keyword(s):  
Laser Beam ◽  
Bonding Strength ◽  
Steel Substrate ◽  
Dendritic Structure ◽  
Plasma Coating ◽  
Alloy Coating ◽  
Laser Remelting ◽  
Globular Structure ◽  
Metastable Structures ◽  
Boride Phases

Abstract In the present paper, the bonding strength of Fe-based self-fluxing alloy coating deposited by plasma spraying, gluing and laser remelting and alloying on the steel substrate have been investigated. When flame melting, a globular structure is formed. Against the background of the solid solution carbide-boride phases are clearly distinguishable, between which the Fe–Fe2B and Fe–FeB eutectic colonies are situated. Laser remelting leads to the formation of metastable structures, reinforced with dendrites, consisting of alloyed Fe-α and Fe-γ. At the low laser beam speeds the coating is melted completely with the formation of a cast structure with the dendrites. When the laser beam speed is increased, the dendritic structure gets fragmented. Structures of coatings alloyed with B4C and remelted by the laser beam vary with the increase of the spot speed. The bonding strength of coating without subsequent remelting decreases by 4–5 times in comparison with remelted. The bonding strength of the reinforced glue coating has adhesive and adhesive-cohesive character. When the load increases in the coating, microcracks develop, which gradually spread to the center of the bonding surface. For plasma coatings after laser remelting without additional alloying, the maximum bonding strength is observed with the minimum laser beam speed. With increasing the laser beam speed it decreases almost 1.5 times. In glue coatings reinforced with B4C particulates by laser remelting, the bonding strength is lower by 1.2–1.4 times in comparison with plasma coating.

Effect of Mo Addition to ZA22 Alloy Grain Refined by Ti-B on its Metallurgical and Mechanical Characteristics in the as Cast Condition

2017 ◽  
Vol 886 ◽  
pp. 64-68 ◽  
Author(s):  
Safwan M.A. Al-Qawabah ◽  
Adnan I.O. Zaid
Keyword(s):  
Phase Diagram ◽  
Grain Size ◽  
Rare Earth ◽  
Mechanical Characteristics ◽  
Aluminum Content ◽  
Dendritic Structure ◽  
High Strength ◽  
Zinc Alloys ◽  
Molybdenum Addition ◽  
Cast Condition

Zinc aluminum alloys are getting increasingly in use in industrial and engineering applications especially after the development of zinc alloys with higher aluminum content. These new developed zinc aluminum based alloys have high strength and hardness, improved creep and wear resistances and lower density. However they have the disadvantage of solidifying in dendritic structure with large grain size which adversely affects their mechanical strength, toughness and surface quality. Grain refinement of metals and alloys by rare earth elements has engaged the materials researchers for the last seven decades. In this paper the effect of molybdenum addition diagram to zinc 22 wt. % aluminum, ZA22, alloy grain refined by Ti-B at a rate of 0.1 wt. %, which corresponds to the peretictic point on the Al-Zn phase diagram in the as cast condition was carried out. The effect of the addition on the metallurgical and mechanical characteristics of the alloy were investigated and the obtained results are presented and discussed.

Oncornavirus assembly at the cell surface revealed in replicas of freeze-dried cells

1978 ◽  
Vol 36 (2) ◽  
pp. 354-355
Author(s):  
Anthony Demsey ◽  
Christopher W. Stackpole
Keyword(s):  
Cell Surface ◽  
Surface Membrane ◽  
Viral Origin ◽  
Intact Cells ◽  
Structural Formation ◽  
Virus Core ◽  
Freeze Dried ◽  
Cacodylate Buffer ◽  
Surface Replica ◽  
Leukemia Viruses

The murine leukemia viruses are type-C oncornaviruses, and their release from the host cell involves a “budding” process in which the newly-forming, RNA-containing virus core becomes enveloped by modified cell surface membrane. Previous studies revealed that the released virions possess a dense array of 10 nm globular projections (“knobs”) on this envelope surface, and that these knobs contain a 70, 000 MW glycoprotein (gp70) of viral origin. Taking advantage of this distinctive structural formation, we have developed a procedure for freeze-drying and replication of intact cells which reveals surface detail superior to other surface replica techniques, and sufficient to detect even early stages of virus budding by localized aggregation of these knobs on the cell surface.Briefly, cells growing in monolayer are seeded onto round glass coverslips 10-12 mm in diameter. After a period of growth, cells are fixed in situ for one hour, usually with 1% OsO4 in 0. 1 M cacodylate buffer, and rinsed in distilled water.

Mechanical characteristics of the EGJ after fundoplication compared to normal subjects and GERD patients

2001 ◽  
Vol 120 (5) ◽  
pp. A112-A112 ◽  
Author(s):  
J CURRY ◽  
G SHI ◽  
J PANDOLFINO ◽  
R JOEHL ◽  
J BRASSEUR ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Normal Subjects

Estimation of Mechanical Characteristics of Cement Treated Demolition Waste

2011 ◽  
Author(s):  
Dongxing Xuan ◽  
André A. A. Molenaar ◽  
Lambert J. M. Houben ◽  
Zhonghe Shui
Keyword(s):  
Mechanical Characteristics ◽  
Demolition Waste
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