Microwave Annealing of Cold Compression Deformation Red Copper

2011 ◽  
Vol 199-200 ◽  
pp. 1840-1844
Author(s):  
Wen He ◽  
Yun Long Ai ◽  
Jia Yuan Ding ◽  
Li Liu ◽  
Fei He

Annealing treatment of cold compression deformation red copper was heated by microwave. The feasibility of microwave heating technology applied to heat treatment of metallic materials, and the effect of annealing process on microstructure were discussed. The results show that the phenomenon of arc discharge do not occur during the process of microwave heating red copper, which illustrates that microwave can be used as heat source for heat treatment of metallic materials. When annealing condition is 510°C for 30min, the grains of deformation red copper undergo a transition from fibrous grain to equiaxial grain, and it completes recrystallization. Compared with traditional annealing treatment, microwave annealing treatment can prevent oxidation phenomenon of specimen surface effectively, reduce annealing temperature, shorten heating and holding time, reduce the consumption of energy greatly, and the degree of hardness decline is smaller under the same annealing condition.

2013 ◽  
Vol 58 (3) ◽  
pp. 919-922 ◽  
Author(s):  
K. Granat ◽  
B. Opyd ◽  
D. Nowak ◽  
M. Stachowicz ◽  
G. Jaworski

Abstract The paper describes preliminary examinations on establishing usefulness criteria of foundry tooling materials in the microwave heating technology. Presented are measurement results of permittivity and loss tangent that determine behaviour of the materials in electromagnetic field. The measurements were carried-out in a waveguide resonant cavity that permits precise determination the above-mentioned parameters by perturbation technique. Examined were five different materials designed for use in foundry tooling. Determined was the loss factor that permits evaluating usefulness of materials in microwave heating technology. It was demonstrated that the selected plastics meet the basic criterion that is transparency for electromagnetic radiation.


2020 ◽  
Vol 39 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Siwen Tang ◽  
Rui Wang ◽  
Pengfei Liu ◽  
Qiulin Niu ◽  
Guoqing Yang ◽  
...  

AbstractWith the concern of the environment, green dry cutting technology is getting more and more attention and self-lubricating tool technology plays an important role in dry cutting. Due to the demand for high temperature performance of tools during dry cutting process, cemented carbide with Ni3Al as the binder phase has received extensive attention due to its excellent high temperature strength and high temperature oxidation resistance. In this paper, WC-TiC-Ni3Al-CaF2 graded self-lubricating material and tools were prepared by microwave heating method, and its microstructure, mechanical properties and cutting performance were studied. Results show that gradient self-lubricating material can be quickly prepared by microwave heating technology, and the strength is equivalent to that of conventional heating technology. CaF2 not only plays a role in self-lubrication, but also refines the grain of the material. A reasonable gradient design can improve the mechanical properties of the material. When the gradient distribution exponent is n1 = 2, the material has high mechanical properties. Cutting experiments show that the WC-TiC-Ni3Al-CaF2 functional gradient self-lubricating tool has better cutting performance than the homogeneous WC-TiC-Ni3Al hard alloys.


Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 265
Author(s):  
Chun-Liang Chen ◽  
Sutrisna

Refractory high-entropy alloy (RHEA) is one of the most promising materials for use in high-temperature structural materials. In this study, the WMoNbTaV coatings on 304 stainless steel substrates has been prepared by mechanical alloying (MA). Effects of V addition and subsequent heat treatment on properties of the WMoNbTaV coatings were investigated. The results show that the RHEA coatings with nanocrystalline body-centered cubic (BCC) solid-solution phase were generated by the mechanical alloying process. The presence of the V element promotes a uniform microstructure and homogeneous distribution of composition in the RHEA coatings due to improving alloying efficiency, resulting in an increase of hardness. After the annealing treatment of the RHEA coatings, microstructure homogeneity was further enhanced; however, the high affinity of Ta for oxygen causes the formation of Ta-rich oxides. Annealing also removes strain hardening generated by high-energy ball milling and thus decreases the hardness of the RHEA coating and alters microstructure evolution and mechanical properties.


2014 ◽  
Vol 1666 ◽  
Author(s):  
Tomohiko Nakamura ◽  
Shinya Yoshidomi ◽  
Masahiko Hasumi ◽  
Toshiyuki Sameshima ◽  
Tomohisa Mizuno

ABSTRACTWe report crystallization of amorphous silicon (a-Si) thin films and improvement of thin film transistors (TFTs) characteristics using 2.45 GHz microwave heating assisted with carbon powders. Undoped 50-nm-thick a-Si films were formed on quartz substrates and heated by microwave irradiation for 2, 3, and 4 min. Raman scattering spectra revealed that the crystalline volume ratio increased to 0.42 for the 4-min heated sample. The dark and photo electrical conductivities measured by Air mass 1.5 at 100 mW/cm2 were 2.6x10-6 and 5.2x10-6 S/cm in the case of 4-min microwave heating followed by 1.3x106-Pa-H2O vapor heat treatment at 260°C for 3 h. N channel polycrystalline silicon TFTs characteristics were improved by the combination of microwave heating with high-pressure H2O vapor heat treatment. The threshold voltage decreased from 5.3 to 4.2 V and the effective carrier mobility increased from 18 to 25 cm2/Vs.


2014 ◽  
Vol 936 ◽  
pp. 1694-1700
Author(s):  
Zhi Wei Li ◽  
Kai Yong Jiang ◽  
Fei Wang ◽  
Ji Liang Zhang

This paper mainly introduces the mechanism of microwave heating: electric conduction loss, eddy current loss and arc discharge. The microwave heating behavior of 316 stainless steel powder body which made by gel casting was investigated in the paper. Experiments on different microwave power, powder particle size, and the content of auxiliary heating material showed that the smaller the powder particle size, the larger microwave power and auxiliary heating materials help 316 stainless steel body for sintering.


2012 ◽  
Vol 271-272 ◽  
pp. 17-20
Author(s):  
Shu Yan Wu ◽  
Ze Sheng Ji ◽  
Chun Ying Tian ◽  
Ming Zhong Wu

This work is to study the influence of heat treatment on microstrudture and mechanical properties of AZ31B magnesium alloy prepared by solid -state recycling. AZ31B magnesium alloy chips were recycled by hot extruding. Three different heat treatments were conducted for recycled alloy. Mechanical properties and microstructure of the recycled specimen and heat treated specimen were investigated. 300°C×2h annealing specimen exhibits finer grain due to static recrystallization, and microstructure of 400°C×2h annealing specimen becomes more coarse. 300°C×2h annealing treatment improves obviously strength and ductility of recycled alloy. Ultimate tensile strength of alloy decreases and elongation to failure increases after 400°C×2h annealing. Grain size, dislocation density and bonding of chips have an effect on the elongation of recycled materials. 190°C×8h ageing has no influence on microstructure and mechanical properties of recycled alloy.


2017 ◽  
Vol 17 (3) ◽  
pp. 55-58
Author(s):  
A. Jarco

Abstract The paper presents research on the effects of soft annealing parameters on a change of the impact strength KC and Brinell hardness (HB) of the EN AC-AlSi11 alloy. The research has been performed according to the trivalent testing plan for two input parameters – temperature in the range between 280°C and 370°C and time in the range between 2 and 8 hours. The application of such heat treatment improves the plasticity of the investigated alloy. The improvement of the impact strength KC by 71% and the decrease of the hardness HB by 20% was achieved for the soft annealing treatment conducted at a temperature 370°C for 8 hours, compared to the alloy without the heat treatment. A change of the form of eutectic silicon precipitations which underwent refinement, coagulation and partial rounding, had a direct effect on the hardness HB and impact strength KC. The results obtained were used to prepare space plots enabling the temperature and time for soft annealing treatment to be selected with reference to the obtained impact strength KC and hardness HB of the alloy with the heat treatment.


2020 ◽  
Vol 7 (3) ◽  
pp. 196-206
Author(s):  
Shunda Lin ◽  
Mamdouh Omran ◽  
Shenghui Guo

: Microwave heating technology is considered one of the most likely to replace traditional heating methods due to its efficient, quick, and green heating transmission that meets the requirements of sustainable development. Microwave heating can strengthen chemical reactions and change the morphology of minerals, and it can save energy and achieve rapid and efficient heating, clean production, and emission reduction. Therefore, this paper summarizes the research status of microwave heating in the recovery of valuable metals (Cu, Au, V),) from metallurgical waste ore and rare earth elements from rare earth minerals in recent years, expounds the principle of microwave heating, and summarizes the previous experimental phenomena. Finally, the development potential, opportunities, and difficulties of microwave technology in future industrial applications are discussed.


Author(s):  
Patricia Jovičević-Klug ◽  
Bojan Podgornik

Deep cryogenic treatment (DCT) is a type of cryogenic treatment, where a metallic material is subjected to temperatures below -150°C, normally to temperatures of liquid nitrogen (-196 °C). When a material is exposed to DCT as a part of heat treatment, changes in microstructure are induced due to new grain formation, changes in grain size, change in the solubility of atoms, movement of dislocations, alteration of crystal structure, and finally new phase formation. The metallic material's performance and later performance of manufactured components and tools from this specific material are dependent on the selection of proper design, proper material, accuracy with which the tool is made and application of proper heat treatment, including any eventual DCT. Metallic materials are ferrous and non-ferrous metals. In the last years ferrous metals (different grades of steel) and non-ferrous alloys (aluminum, magnesium, titanium, nickel etc.) have been increasingly treated with DCT to alter their properties. DCT treatment has shown to reduce density of defects in crystal structure, increase wear resistance of material, increase hardness, improve toughness, and reduce tensile strength and corrosion resistance. However, some researchers also reported results showing no change in properties (toughness, hardness, corrosion resistance, etc.) or even deterioration when subjected to DCT treatment. This leads to a lack of consistency and reliability of the treatment process, which is needed for successful application in industry. This review provides a synopsis of DCT usage and resulting effects on treated materials used in automotive industry.


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