烧结钕铁硼的层裂强度及断裂机理

万印; 王焕然; 初广香; 任春影

doi:10.11858/gywlxb.20190746

烧结钕铁硼的层裂强度及断裂机理

doi: 10.11858/gywlxb.20190746

宁波大学冲击与安全工程教育部重点实验室，浙江宁波　315211

基金项目: 国家自然科学基金（11572164）

详细信息

作者简介:
万　印（1993－），男，硕士研究生，主要从事冲击动力学研究. E-mail: 1049570443@qq.com

通讯作者:
王焕然（1976－），男，博士，副教授，主要从事冲击动力学研究. E-mail: wanghuanran@nbu.edu.cn

中图分类号: O347.1; TM273
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出版历程
- 收稿日期: 2019-03-25
- 修回日期: 2019-04-22

Spall Strength and Fracture Mechanism of Sintered Nd-Fe-B

Key Laboratory of Impact and Engineering of Ministry of Education, Ningbo University, Ningbo 315211, China

摘要

摘要: 利用一级气体炮对烧结钕铁硼（Nd-Fe-B）永磁材料进行平板撞击实验，实现一维应变下的层裂；采用激光干涉测速技术，测量样品自由面粒子速度历史，确定了冲击压缩后层裂强度与加载应力的关系。结果表明：加载应力在0.375～2.512 GPa范围内时，层裂强度随着加载应力的增加先增加后减小，存在一个阈值，当加载应力超过该阈值时，材料发生压缩损伤，层裂强度随之减小。通过扫描电子显微镜观察样品断口形貌，发现在冲击载荷下烧结钕铁硼出现明显的穿晶断裂。
- 烧结钕铁硼 /
- 层裂强度 /
- 断裂机理 /
- 穿晶断裂
Abstract: The plate impact experiment was carried out through use of one-stage gas gun platform to study the spall of sintered Nd-Fe-B magnet subjected to one-dimensional loading. The free-surface velocity profile was measured using fiber velocity interferometer system for any reflector, and the spall strength was determined. The main results show that spall strength increases and then decreases when the impact stress increases from 0.377 GPa to 2.512 GPa. The reason is attributed to compression damage of the material when the impacted stress exceeds a stress threshold. Furthermore, the fractured morphology of sinter Nd-Fe-B was analyzed by scanning electron microscopy and the transgranular fracture was observed.
- sintered Nd-Fe-B /
- spall strength /
- fracture mechanism /
- transgranular fracture

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图 1 实验装置示意图

Figure 1. Schematic of experimental setup

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图 2 层裂原理示意图

Figure 2. Schematic illustration of spall process

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图 4 层裂强度与加载应力的关系

Figure 4. The relationship between spall strength and impact stress

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图 3 层裂实验样品的自由面速度剖面

Figure 3. Free surface velocity profile of the sample in the spall experiment

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图 5 断口的SEM图像

Figure 5. SEM images of the fractured surface

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表 1 飞片材料的Hugoniot参数^[9]

Table 1. Hugoniot parameters of flyers^[9]

Material	${\rho _{0{\rm{i}}}}$$/({\rm{g}} \cdot {\rm{c}}{{\rm{m}}^{ - 3}})$	${c_{0{\rm{i}}}}$$/({\rm{km}} \cdot {{\rm{s}}^{ - 1}})$	${\lambda _{\rm{i}}}$
PMMA	1.186	2.65	1.54
LY12	2.784	5.37	1.29

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表 2 烧结钕铁硼层裂实验参数和结果

Table 2. Parameters and results of spall experiments for Nd-Fe-B

Exp. No.	Material of flyer	Thickness of flyer/mm	V/(m·s^–1)	Thickness of sample/mm	$\sigma $/GPa	${\sigma _{{\rm{sp}}}}$/GPa
01	PMMA	1.17	122.67	3.99	0.375	0.209
02	PMMA	1.16	173.99	3.99	0.550	0.249
03	PMMA	1.17	230.72	3.96	0.739	0.263
04	LY12	2.28	146.33	3.95	1.591	0.274
05	LY12	2.33	161.90	3.90	1.737	0.313
06	LY12	2.28	190.89	3.94	2.092	0.251
07	LY12	2.34	230.73	3.95	2.512	0.224

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参考文献(11)

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