Microstructure and property evolution of isotropic and anisotropic NdFeB magnets fabricated from nanocrystalline ribbons by spark plasma sintering and hot deformation

2010 ◽  
Vol 44 (2) ◽  
pp. 025003 ◽  
Author(s):  
Z W Liu ◽  
H Y Huang ◽  
X X Gao ◽  
H Y Yu ◽  
X C Zhong ◽  
...  
2020 ◽  
Vol 39 (1) ◽  
pp. 457-465
Author(s):  
Jiangpeng Yan ◽  
Zhimin Zhang ◽  
Jian Xu ◽  
Yaojin Wu ◽  
Xi Zhao ◽  
...  

AbstractThe cylindrical samples of TC4 titanium alloy prepared by spark plasma sintering (SPS) were compressed with hot deformation of 70% on the thermosimulation machine of Gleeble-1500. The temperature of the processes ranged from 850°C to 1,050°C, and the strain rates varied between 0.001 and 5 s−1. The relative density of the sintered and compressed samples was measured by the Archimedes principle. During hot deformation, the microstructure of the sample was observed. The results show that the average relative density of the samples was 90.2% after SPS. And the relative density was about 98% after the hot deformation of 70%. Under high temperature (>950°C), the sensitivity of flow stress to temperature was reduced. At low strain rate (0.001 s−1), the increase in the deformation temperature promoted the growth of dynamic recrystallization (DRX). At the same temperature, the increase in strain rate slowed down the growth of DRX grains. And the variation tendency was shown from the basket-weave structure to the Widmanstätten structure at a low strain rate (<0.1 s−1), with increase in the strain rate.


2014 ◽  
Vol 802 ◽  
pp. 585-589 ◽  
Author(s):  
M. Alberteris Campos ◽  
N. Vicente ◽  
I.F. Machado ◽  
K.S.T. de Souza ◽  
D. Rodrigues ◽  
...  

The shortage of dysprosium as an alloying element has directed the research on the grain size refining of NdFeB, since higher coercivities can be obtained by decreasing the grain size, without Dy addition. The Spark Plasma Sintering (SPS) is a consolidation process which allows densification at lower temperatures and shorter dwell times of sintering, thus avoiding the grain growth. Therefore, the typical temperature of sintering of NdFeB magnets can be decreased from 1050°C to around 800°C, as it was evidenced by means of SPS shrinkage curves and the high densified microestructure obtained in this work.


Sign in / Sign up

Export Citation Format

Share Document