Directional Solidification of Nd-Fe-B Alloys with High Temperature Gradient

Zhong Hong; Li Shuangming; Lu Haiyan; Liu Lin; Zou Guangrong; Fu Hengzhi

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Directional Solidification of Nd-Fe-B Alloys with High Temperature Gradient
Issue 4, Pages: 251-253(2008)
Published： 2008 ，
DOI：

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[1]钟宏,李双明,吕海燕,刘林,邹光荣,傅恒志.Nd-Fe-B包晶合金高梯度定向凝固试验研究[J].特种铸造及有色合金,2008(04):251-253+241.

Zhong Hong, Li Shuangming, Lu Haiyan, et al. Directional Solidification of Nd-Fe-B Alloys with High Temperature Gradient. [J]. Special Casting & Nonferrous Alloys (4):251-253(2008)
[1]钟宏,李双明,吕海燕,刘林,邹光荣,傅恒志.Nd-Fe-B包晶合金高梯度定向凝固试验研究[J].特种铸造及有色合金,2008(04):251-253+241. DOI：

Zhong Hong, Li Shuangming, Lu Haiyan, et al. Directional Solidification of Nd-Fe-B Alloys with High Temperature Gradient. [J]. Special Casting & Nonferrous Alloys (4):251-253(2008) DOI：

摘要

在定向凝固试验中

采用全熔和区熔两种加热方式分别获得了180K/cm和250～360K/cm的温度梯度

在5～500μm/s的抽拉速率范围内对过包晶Nd13.5Fe79.75B6.75合金进行了定向凝固试验

考察了温度梯度和抽拉速率对此合金凝固组织及相含量的影响。结果表明

合金的凝固组织包含初生α-Fe枝晶、包晶Nd2Fe14B相及少量的富Nd相。随着抽拉速率的增加

包晶相含量先增加后减少;而在同一抽拉速率下

提高温度梯度可增加铁磁性Nd2Fe14B相的含量。当抽拉速率为50μm/s时

区熔试样中（G=300K/cm）Nd2Fe14B相的含量可达约90%

而相同速率下全熔试样（G=180K/cm）中其含量约为60%。

Abstract

Directional solidification experiments were performed on peritectic Nd13.5 Fe79.75 B6.75 alloy with temperature gradient of 180 K/cm and 250-360 K/cm obtained from total melting and zone melting

respectively

at pulling velocity ranging from 5 to 500μm/s to investigate the effects on microstructure and phase constituent in the alloy.The results indicate that the microstructure of the alloy is composed of primary α-Fe dendrites

peritectic Nd2Fe14B phase and minor Nd-rich phase.The volumetric fraction of ferromagnetic Nd2Fe14B phase is firstly increased and then decreased with rising the pulling velocity

and is improved with increasing temperature gradient.Grown at 50μm/s

the volumetric fraction of ferromagnetic Nd2Fe14 B phase reaches up to 90% in the zone melting specimens（given a temperature gradient at 300 K/cm）

which is about 30% higher than that in the total melting specimens（given a temperature gradient at 180 K/cm）.