scholarly journals Manufacturing of High-Performance Bi-Metal Bevel Gears by Combined Deposition Welding and Forging

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 898 ◽  
Author(s):  
Anna Chugreeva ◽  
Maximilian Mildebrath ◽  
Julian Diefenbach ◽  
Alexander Barroi ◽  
Marius Lammers ◽  
...  
Keyword(s):  
High Performance ◽  
Elevated Temperatures ◽  
Hot Forging ◽  
Welding Process ◽  
Main Idea ◽  
Material System ◽  
Typical Structure ◽  
Geometrical Properties ◽  
Bevel Gears ◽  
Tailored Forming

The present paper describes a new method concerning the production of hybrid bevel gears using the Tailored Forming technology. The main idea of the Tailored Forming involves the creation of bi-metal workpieces using a joining process prior to the forming step and targeted treatment of the resulting joint by thermo-mechanical processing during the subsequent forming at elevated temperatures. This improves the mechanical and geometrical properties of the joining zone. The aim is to produce components with a hybrid material system, where the high-quality and expensive material is located in highly stressed areas only. When used appropriately, it is possible to reduce costs by using fewer high-performance materials than in a component made of a single material. There is also the opportunity to significantly increase performance by combining special load-tailored high-performance materials. The core of the technology consists in the material-locking coating of semi-finished parts by means of plasma-transferred-arc welding (PTA) and subsequent forming. In the presented investigations, steel cylinders made of C22.8 are first coated with the higher-quality heat-treatable steel 41Cr4 using PTA-welding and then hot-formed in a forging process. It could be shown that the applied coating can be formed successfully by hot forging processes without suffering any damage or defects and that the previous weld structure is completely transformed into a homogeneous forming-typical structure. Thus, negative thermal influences of the welding process on the microstructure are completely neutralized.

ALCOA 351 SUPRACAST

Alloy Digest ◽  
2020 ◽  
Vol 69 (7) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Copper Alloy ◽  
High Performance ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Aluminum Silicon

Abstract Alcoa 351 SupraCast is a heat-treatable aluminum-silicon-copper alloy that also contains small amounts of magnesium, manganese, vanadium, and zirconium. It is designed for components exposed to elevated temperatures in high performance engines. This datasheet provides information on composition, physical properties, and tensile properties as well as fatigue. It also includes information on heat treating, machining, and joining. Filing Code: Al-466. Producer or source: Alcoa Corporation.

BERYLCO 25S

Alloy Digest ◽  
1952 ◽  
Vol 1 (3) ◽  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Precipitation Hardening ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Good Resistance ◽  
Subzero Temperatures ◽  
Endurance Strength ◽  
Wear And Corrosion ◽  
Resistance To Wear

Abstract Berylco 25S alloy is the high-performance beryllium-copper spring material of 2 percent nominal beryllium content. It responds to precipitation-hardening for maximum mechanical properties. It has high elastic and endurance strength, good electrical and thermal conductivity, excellent resistance to wear and corrosion, high corrosion-fatigue strength, good resistance to moderately elevated temperatures, and no embrittlement or loss of normal ductility at subzero temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-3. Producer or source: Beryllium Corporation.

Ultra-thin two-dimensional molecular crystals grown on a liquid surface for high-performance phototransistors

2021 ◽  
Author(s):  
Shuyuan Yang ◽  
Yu Zhang ◽  
Ying Wang ◽  
Jiarong Yao ◽  
Lijuan Zhang ◽  
...  
Keyword(s):  
Organic Semiconductor ◽  
High Performance ◽  
Elevated Temperatures ◽  
Liquid Surface ◽  
Molecular Crystals ◽  
Two Dimensional ◽  
Poor Solubility

Bilayer 2D molecular crystals of an organic semiconductor with poor solubility were grown on a liquid substrate at elevated temperatures. The molecularly thin crystals exhibited superior mobility and photoresponse.

Thermal Spraying of High Performance Thermoplastics

1998 ◽  
Author(s):  
E. Lugscheider ◽  
C. Herbst ◽  
A. Fischer
Keyword(s):  
High Performance ◽  
Elevated Temperatures ◽  
Thermal Spraying ◽  
Paper Coatings ◽  
Thermally Sprayed Coatings ◽  
Ft Ir ◽  
Ir Analysis ◽  
Thermally Sprayed ◽  
Sprayed Coatings ◽  
Wipe Tests

Abstract Thermally sprayed coatings of high performance thermoplastics are of interest espacially for the chemical industry for anti-corrosion applications at elevated temperatures. In this paper coatings of polyetherether-keton (PEEK) and polyphenylen-sulphide (PPS) have been produced by simple flamespraying. They have been investigated by optical metallography, FT-IR analysis and DSC-analysis. Among the coating properties also the "in-flight" particles have been studied by wipe-tests and FT-IR analysis in order to assess possible decomposition effects during spraying.

Features of structure formation processes in AA2024 alloy joints formed by the friction stir welding with bobbin tool

2021 ◽  
Vol 23 (2) ◽  
pp. 98-115
Author(s):  
Alexey Ivanov ◽  
◽  
Valery Rubtsov ◽  
Andrey Chumaevskii ◽  
Kseniya Osipovich ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Structure Formation ◽  
Welded Joints ◽  
Heat Input ◽  
Welded Joint ◽  
Welding Process ◽  
Tool Material ◽  
Travel Speed ◽  
Material System ◽  
Friction Stir

Introduction. One of friction stir welding types is the bobbin friction stir welding (BFSW) process, which allows to obtain welded joints in various configurations without using a substrate and axial embedding force, as well as to reduce heat loss and temperature gradient across the welded material thickness. This makes the BFSW process effective for welding aluminum alloys, which properties are determined by their structural-phase state. According to research data, the temperature and strain rate of the welded material have some value intervals in which strong defect-free joints are formed. At the same time, much less attention has been paid to the mechanisms of structure formation in the BFSW process. Therefore, to solve the problem of obtaining defect-free and strong welded joints by BFSW, an extended understanding of the basic mechanisms of structure formation in the welding process is required. The aim of this work is to research the mechanisms of structure formation in welded joint of AA2024 alloy obtained by bobbin tool friction stir welding with variation of the welding speed. Results and discussion. Weld formation conditions during BFSW process are determined by heat input into a welded material, its fragmentation and plastic flow around the welding tool, which depend on the ratio of tool rotation speed and tool travel speed. Mechanisms of joint formation are based on a combination of equally important processes of adhesive interaction in “tool-material” system and extrusion of metal into the region behind the welding tool. Combined with heat dissipation conditions and the configuration of the “tool-material” system, this leads to material extrusion from a welded joint and its decompaction. This results in formation of extended defects. Increasing in tool travel speed reduce the specific heat input, but in case of extended joints welding an amount of heat released in joint increases because of specific heat removal conditions. As a result, the conditions of adhesion interaction and extrusion processes change, which leads either to the growth of existing defects or to the formation of new ones. Taking into account the complexity of mechanisms of structure formation in joint obtained by BFSW, an obtaining of defect-free joints implies a necessary usage of various nondestructive testing methods in combination with an adaptive control of technological parameters directly in course of a welding process.

scholarly journals Mixed Metal-Antimony Oxide Nanocomposites: Low pH Water Oxidation Electrocatalysts with Outstanding Durability at Ambient and Elevated Temperatures

2021 ◽  
Author(s):  
Luke Sibimol ◽  
Manjunath Chatti ◽  
Asha Yadav ◽  
Brittany Kerr ◽  
Jiban Kangsabanik ◽  
...  
Keyword(s):  
Water Oxidation ◽  
High Performance ◽  
Density Functional ◽  
High Stability ◽  
Proton Exchange Membrane ◽  
Elevated Temperatures ◽  
Antimony Oxide ◽  
Proton Exchange ◽  
Efficient Production ◽  
Ambient Conditions

Proton-exchange membrane water electrolysers provide many advantages for the energy-efficient production of H<sub>2</sub>, but the current technology relies on high loadings of expensive iridium at the anodes, which are often unstable in operation. To address this, the present work scrutinises the properties of antimony-metal (Co, Mn, Ni, Fe, Ru) oxides synthesised as flat thin films by a solution-based method for the oxygen evolution reaction in 0.5 M H<sub>2</sub>SO<sub>4</sub>. Among the non-noble-metal catalysts, only cobalt-antimony and manganese-antimony oxides demonstrate high stability and reasonable activity under ambient conditions, but slowly lose activity at elevated temperatures. The ruthenium-antimony system is highly active, requiring an overpotential of 0.39 ± 0.03 and 0.34 ± 0.01 V to achieve 10 mA cm<sup>-2</sup> at 24 ± 2 and 80 °C, respectively, and remaining remarkably stable during one-week tests at 80 °C. The <i>S</i>-number for this catalyst is higher than that for the high-performance benchmark Ir-based systems. Density functional theory analysis and physical characterisation reveal that this high stability is supported by the enhanced hybridisation of the oxygen p- and metal d-orbitals induced by antimony, and can arise from two distinct structural scenarios: either formation of an antimonate phase, or nanoscale intermixing of metal and antimony oxide crystallites.

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