Investigation on the Improvement of Magnetic Properties by Hot Deformation Processes for NdFeB Magnets

2014 ◽  
Vol 626 ◽  
pp. 317-322 ◽  
Author(s):  
Yen Ju Chen ◽  
Chao Cheng Chang ◽  
Po Jen Hsiao ◽  
Can Xun Chang
Keyword(s):  
Plastic Deformation ◽  
Magnetic Properties ◽  
Strain Rate ◽  
Process Parameters ◽  
Effective Strain ◽  
High Energy ◽  
Experimental Results ◽  
Ndfeb Magnets ◽  
Energy Product ◽  
Key Factor

Traditionally, NdFeB magnets with high remanent flux density or high energy product could only be manufactured through altering the material compounds. In recent years, studies indicated that the magnet properties of NdFeB magnets could be improved through plastic deformation. These studies pointed out that the degree of plastic deformation is a key factor to improve magnetic properties. However, there are still many other process parameters that could affect the magnetic properties either positively or negatively. In this paper, process parameters such as strain, strain rate, and temperature are studied to illustrate their influences on the magnetic properties of NdFeB magnets. The magnetic property could be greatly improved when the preferred orientation appears on the microstructure of deformed NdFeB magnets. One of the experimental results showed that the energy product value had been increased by 76.7% when the effective strain value had reached 0.65. Experimental results also showed that strain rate is a dominating factor with regard to the flow stress of material. Through a proper combination of these parameters, one can obtain NdFeB magnets with their magnetic properties greatly improved.

Formability of Explosive Welded Mg/Al Bimetallic Bar

2016 ◽  
Vol 716 ◽  
pp. 114-120 ◽  
Author(s):  
Sebastian Mróz ◽  
Piotr Szota ◽  
Teresa Bajor ◽  
Andrzej Stefanik
Keyword(s):  
Plastic Deformation ◽  
Strain Rate ◽  
Process Parameters ◽  
Metal Forming ◽  
Explosive Welding ◽  
Physical Modelling ◽  
Main Process ◽  
Compression Tests ◽  
Welding Method

The paper presents the results of physical modelling of the plastic deformation of the Mg/Al bimetallic specimens using the Gleeble 3800 simulator. The plastic deformation of Mg/Al bimetal specimens characterized by the diameter to thickness ratio equal to 1 was tested in compression tests. The aim of this work was determination of the range of parameters as temperature and strain rate that mainly influence on the plastic deformation of Mg/Al bars during metal forming processes. The tests were carried out for temperature range from 300 to 400°C for different strain rate values. The stock was round 22.5 mm-diameter with an Al layer share of 28% Mg/Al bars that had been produced using the explosive welding method. Based on the analysis of the obtained testing results it has been found that one of the main process parameters influencing the plastic deformation the bimetal components is the initial stock temperature and strain rate values.

Magnetic properties prediction of NdFeB magnets by using support vector regression

2014 ◽  
Vol 28 (23) ◽  
pp. 1450177
Author(s):  
Wende Cheng
Keyword(s):  
Magnetic Properties ◽  
Support Vector Regression ◽  
Magnetic Energy ◽  
Practical Method ◽  
Percentage Error ◽  
Support Vector ◽  
Ndfeb Magnets ◽  
Energy Product ◽  
Experimental Process ◽  
Leave One Out

A novel model using support vector regression (SVR) combined with particle swarm optimization (PSO) was employed to construct mathematical model for prediction of the magnetic properties of the NdFeB magnets. The leave-one-out cross-validation (LOOCV) test results strongly supports that the generalization ability of SVR is high enough. Predicted results show that the mean absolute percentage error for magnetic remanence Br, coercivity Hcj and maximum magnetic energy product (BH) max are 0.53%, 3.90%, 1.73%, and the correlation coefficient (R2) is as high as 0.839, 0.967 and 0.940, respectively. This investigation suggests that the PSO-SVR is not only an effective and practical method to simulate the properties of NdFeB , but also a powerful tool to optimatize designing or controlling the experimental process.

Synthesis and Magnetic Properties of MnBi(LTP) Magnets With High-Energy Product

2014 ◽  
Vol 50 (11) ◽  
pp. 1-4 ◽  
Author(s):  
Ki Woong Moon ◽  
Kwang-Won Jeon ◽  
Min Kang ◽  
Min-Kyu Kang ◽  
Yangwoo Byun ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
High Energy ◽  
Energy Product

Structure and Magnetic Properties of Strontium Hexaferrite Nanopowders Prepared by Mechanochemical Synthesis

2006 ◽  
Vol 45 ◽  
pp. 321-326 ◽  
Author(s):  
Cornel Miclea ◽  
Constantin Tanasoiu ◽  
Corneliu Florin Miclea ◽  
I. Spanulescu ◽  
Anca Gheorghiu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Mechanochemical Synthesis ◽  
Milled Powder ◽  
Magnetic Behavior ◽  
High Energy ◽  
Strontium Hexaferrite ◽  
Synthesis Process ◽  
Energy Product ◽  
Suitable Heat Treatment ◽  
Structural Deformations

Strontium hexaferrite nanopowders were prepared by mechanochemical synthesis from strontium and iron oxides using a high energy ball mill after 50 hours of milling. The synthesis process was checked by X-Ray diffractograms on powders milled for different times. The magnetic properties of hexaferrite nanopowder, both compacted and dispersed in a nonmagnetic matrix were determined. Severe stresses and structural deformations were introduced by mechanical processing, but they were eliminated, to a great extent, by a suitable heat treatment of the milled powder at 1000 oC for one and a half hour. Coercivities as high as 6600 Oe and specific magnetization of 65 emu/g were found for annealed noninteracting nanopowders. Such values are very near to the theoretical values for strontium ferrite. The magnetic behavior of such powders can be rather well described by the coherent rotation model of Stoner-Wohlfarth for an assembly of single domain particles oriented at random. Sintered bodies of such powders produced magnets with a high HC of 4600 Oe, a Br of 2100 Gs and an energy product maxim of approximately 1.85 MGOe.

scholarly journals Preliminary results on the effect of plastic deformation on magnetic properties

2017 ◽  
Vol 50 (3) ◽  
pp. 372-375
Author(s):  
Deepak Singh ◽  
Kati Mökkönen ◽  
Jarmo Poutala ◽  
Paavo Rasilo ◽  
Anouar Belahcen ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Magnetic Properties ◽  
Experimental Results ◽  
Electric Steel ◽  
Preliminary Results

In this paper some preliminary results on the eect of plastic deformation onmagnetic properties of an electric steel are presented. Both experimental results and modellingaspects are discussed.

scholarly journals Multi-Pass Stamping Forming a Concave Ring

2020 ◽  
Vol 10 (18) ◽  
pp. 6434
Author(s):  
Song Zhang ◽  
Xuedao Shu ◽  
Jianan Shi ◽  
Zixuan Li
Keyword(s):  
Process Parameters ◽  
Strain Field ◽  
Structural Characteristics ◽  
Production Quality ◽  
Experimental Results ◽  
Stress And Strain ◽  
Dimensional Error ◽  
Stamping Dies ◽  
Key Factor

To improve the production quality and efficiency of the concave ring, a multi-pass stamping technology is used to replace the spinning technology to form the concave ring. First, the multi-pass stamping dies are designed according to the structural characteristics of the concave ring. Then, the process parameters are determined based on the bending conditions and the dimensional requirements of the concave ring. Next, the rationality of the designed stamping dies is verified by analyzing the stress and strain field of the multi-pass stamping concave ring. Finally, the stamping experiments are carried out. Experimental results show that the dimensional error of the concave ring formed by multi-pass stamping is less than 0.5%. The multi-pass stamping technology is feasible to form the concave ring. The reasonable design of the mold is the key factor to prevent defects in the workpiece. The concave ring formed by multi-pass stamping meets the industrial requirements.

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