Control of degradation of materials properties in recycling by grain boundary engineering

通过晶界工程控制回收过程中材料性能的退化

• 批准号: 15201015
• 负责人: TSUREKAWA Sadahiro
• 金额: $ 22.21万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15201015/
• 关键词: recycling; grain boundary engineering; magnetic field; steel; grain boundary segregation; 磁気特性; 粒界性格分布; 急冷凝固法; 双晶; ステンレス鋼; 鉄鉱; 粒界偏析脆化; 粒界エネルギー; 破壊靭性

Today, recycled materials are universally growing in importance because of savings of material resources, energy. However, harmful impurities like Sn and Cu are inevitably contained in scrap steel, and segregate to grain boundaries due to their low solid solubility in iron. Their segregation severely degrades mechanical properties of recycled steel. The motivation of this project was to develop methodology for controlling materials degradation on the basis of grain boundary engineering. The chief results obtained are follows.1. Controlling grain boundary segregation and segregation embrittlement by application of magnetic field : It was found that magnetic annealing of Fe-Sn alloy at 973K in ferromagnetic temperature region could suppress Sn segregation to grain boundaries, resulting in a significant increase of fracture toughness. The higher magnetic field strength, the more increases fracture toughness of Fe-Sn alloys.2. Magnetic property of magnetically annealed Fe-Sn alloy : VSM measurements revealed that coercive force for magnetically annealed Fe-0.8at%Sn alloy decreased with increasing magnetic field strength : i.e., softness of this alloy can be enhanced by magnetic annealing.3. Introduction of insensitive microstructure to grain boundary segregation : We studied materials processing to introduce insensitive microstructure to grain boundary segregation, and found that a rapid solidification was useful to increase a fraction of special boundaries. The fraction of special boundaries was approximately 45% in a rapidly solidified sample, whereas it was 20% in a thermo-mechanically treated one. Three-point bend tests of these samples revealed that the former could show a good plasticity but the latter fractured without showing any plastic deformation.

今天，由于节省了物质资源和能源，回收材料的重要性普遍增加。然而，废钢中不可避免地含有锡、铜等有害杂质，由于它们在铁中的固溶度较低，它们会偏析到晶界。它们的偏析严重降低了回收钢的力学性能。该项目的动机是在晶界工程的基础上开发控制材料降解的方法。取得的主要成果如下：1.研究成果。通过施加磁场控制晶界偏析和偏析脆化：发现在铁磁温区973K的磁退火能抑制锡向晶界的偏析，从而显著提高断裂韧性。磁场强度越高，铁锡合金的断裂韧性越高。磁退火铁锡合金的磁性能：VSM测量表明，磁退火后Fe-0.8at%锡合金的矫顽力随着磁场强度的增加而减小，即磁退火可以提高合金的柔软度。不敏感组织对晶界偏析的引入：我们研究了将不敏感组织引入晶界偏析的材料工艺，发现快速凝固有助于增加特定晶界的比例。在快速凝固的样品中，特殊晶界的比例约为45%，而在热机械处理的样品中，特殊晶界的比例为20%。三点弯曲试验表明，前者表现出良好的塑性，而后者断裂时没有表现出任何塑性变形。

项目成果

Prospect of Grain Boundary Study in Ferromagnetic Materials

铁磁材料晶界研究的展望

• 发表时间: 2004
• 期刊: Materia Japan 43・2
• 作者: T.Watanabe;H.Fujii;SHIGEAKI KOBAYASHI;S.Tsurekawa;Sadahiro Tsurekawa;T.Watanabe;H.Fujii;SHIGEAKI KOBAYASHI;S.Tsurekawa;Sadahiro Tsurekawa;H.Takahashi;S.Tsurekawa;R.Ishibashi;S.Tsurekawa;S.Nakamichi;S.Tsurekawa;T.Watanabe;Shigeaki Kobayashi;T.Watanabe;T.Watanabe;T.Watanabe;R.Ishibashi;S.Tsurekawa;S.Nakamichi;S.Tsurekawa;T.Watanabe;Shigeaki Kobayashi;T.Watanabe;T.Watanabe;T.Watanabe;S.Tsurekawa;T.Watanabe;S.Nakamichi;S.Tsurekawa;川原 浩一;Sadahiro Tsurekawa;T.Watanabe;T.Watanabe;K.Kawahara
• 通讯作者: K.Kawahara

A mechanism of plane matching boundary-assisted α/γ phase transformation in Fe-Cr alloy based on in-situ observation

基于原位观察的Fe-Cr合金平面匹配边界辅助α/γ相变机制

• 发表时间: 2005
• 期刊: Zeitschrift fur Metallkunde 96
• 作者: Saito K;Kim HS;Sakai N;Ishizuka M;Kazusaka A;Fujita;S.;T.Watanabe
• 通讯作者: T.Watanabe

Diffusion of carbon and titanium in γ-iron in a magnetic field and a magnetic field gradient

• DOI: 10.1007/s10853-005-2683-3
• 发表时间: 2005-06-01
• 期刊: JOURNAL OF MATERIALS SCIENCE
• 影响因子: 4.5
• 作者: Nakamichi, S;Tsurekawa, S;Chiba, A
• 通讯作者: Chiba, A

Effect of grain boundary character distribution on stress corrosion cracking behavior in austenitic stainless steels

• DOI: 10.4028/www.scientific.net/msf.475-479.3863
• 发表时间: 2005-01-01
• 期刊: PRICM 5: THE FIFTH PACIFIC RIM INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS AND PROCESSING, PTS 1-5
• 作者: Ishibashi, R;Horiuchi, T;Shoji, T
• 通讯作者: Shoji, T

Determination of Percolation Threshold for Random Boundary Network on the basis of EBSD/OIM Observations

基于 EBSD/OIM 观测的随机边界网络渗滤阈值的确定

• 发表时间: 2006
• 期刊: Materials Science Forum (in press)
• 作者: Ishihara;A.;R.R.Roy;Y.Ohira;F.Kawano;K.Nonaka;K.Yamamoto;V.R.Edgerton;Sadahiro Tsurekawa
• 通讯作者: Sadahiro Tsurekawa