F.R. Cao and J.Z. Cui(Department of Metalforming
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P.O.B 317
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Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
The maximum elongation-to-failure of 960% has been achieved in the Mg-8wt%Li alloy. It is shown by measurement of true stress-strain curve and microstructure observation that dynamic recrystallization takes place during superplastic deformation, which turns the banded grains into equiaxed grains. It is postulated by theoretical analysis that during superplastic deformation,continuous introduction of lattice dislocations into the phase interfaces contributes to the superplasticity in this alloy.During superplastic deformation,grain growth and cavity nucleation at α phase grain boundaries have also been observed.
关键词:
superplasticity
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null
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null
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null
,
null
周曦亚
,
胡俊
,
周斌扬
,
刘林凤
硅酸盐通报
采用烧结法制备了CaO-SiO_2-R_2O-F(R=Na, K)系微晶玻璃,并结合XRD、DTA、SEM等测试方法,探讨了CaF_2含量对CaO-SiO_2-R_2O-F系微晶玻璃晶化行为的影响.结果表明:添加适量的CaF_2能有效地促进微晶玻璃的析晶.在一定热处理制度下,制备出的微晶玻璃内含大量互锁的板条状晶体和针状晶体,主晶相为硅碱钙石和Frankamenite(一种富含氟的硅碱钙石).随着CaF_2含量的增加,晶体的含量逐渐提高,晶体数量逐渐增大,尺寸逐渐减小.
关键词:
微晶玻璃
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硅碱钙石
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晶化行为
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显微结构
H.P. Chen and Z.J. Deng (State Key Lab. for Mechanical Behavior of Materials
,
Xi'an Jiaotong University
,
Xi'an 710049
,
China)
金属学报(英文版)
The effect of specimen thinkness on JR resistance curve has been investigated using low and middle strength steels. As the J dominance regime is reached, the initial J-integral values, J(i), are definite even if the elastic component Ji(e) and plastic component Ji(p)vary with the thinkness of specimen. The wider the specimen width, the larger the Ji(e)/Ji and the smaller the Ji(p)/Ji. The crack propagation resistance, dJR/da and dJp/da, decreases, while dJe/da increases linearly with increasing specimen thinness.Based on the above experimental results, an empirical formula dJ/da = α+β. B is given, which can be used to evaluate the safety of practical structural components.A modified J-integral is presented, upon which a new view is Put forward that the increase in crack growth resistance is induced mainly by the increase in the plastic J-integral component with the crack propagation,
关键词:
: fracture mechanics
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null
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null
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null
材料科学技术(英文)
Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar structure, interface morphology, and metastable phase presented at the interface of the multilayer system strongly depend on the bilayer thickness (Lambda). For high period multilayers, the waviness wavelength of interfaces is about two times broader than the column diameter. For a sample with Lambda =30 nm, its column width and waviness wavelength was about 80, and 190 nm, respectively. Both of them decreased with the reduction of Lambda, so as to nearly equal values of column diameter and waviness wavelength were obtained. The Fe and Ti grains of both 30 nm and 6 nm multilayers are polycrystalline, and have a textured structure. In short bilayer thickness (Lambda =6 nm), the intermetallic compound Fe2Ti was presented at the interfaces due to solid state reaction; for Lambda =2 nm, amorphous phase Ti-rich layer was formed at the interfaces, resulting in a sharp interface multilayer structure.
关键词:
model;films
Wei WANG
,
Lishi WEN
材料科学技术(英文)
Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar structure, interface morphology, and metastable phase presented at the interface of the multilayer system strongly depend on the bilayer thickness (Lambda). For high period multilayers, the waviness wavelength of interfaces is about two times broader than the column diameter. For a sample with Lambda =30 nm, its column width and waviness wavelength was about 80, and 190 nm, respectively. Both of them decreased with the reduction of Lambda, so as to nearly equal values of column diameter and waviness wavelength were obtained. The Fe and Ti grains of both 30 nm and 6 nm multilayers are polycrystalline, and have a textured structure. In short bilayer thickness (Lambda =6 nm), the intermetallic compound Fe2Ti was presented at the interfaces due to solid state reaction, for Lambda =2 nm, amorphous phase Ti-rich layer was formed at the interfaces, resulting in a sharp interface multilayer structure.
关键词:
许少普
,
崔冠军
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李治强
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杨东
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庞百鸣
,
张智慧
钢铁研究
采用模铸浇注、3 800 mm轧机轧制、正火热处理工艺成功地开发并批量生产了82 mm厚Q345R-Z35锅炉压力容器用钢板,钢板超声波探伤全部符合JB/T 4730--2008一级标准,钢板屈服强度平均为350 MPa,抗拉强度平均为520 MPa,伸长率平均值为28%,平均冲击功为144 J,抗层状撕裂厚度拉伸性能全部合格,抗氢致开裂性(HIC)试验检测结果表明:裂纹敏感率、裂纹长度率、裂纹宽度率均为0.
关键词:
抗氢致裂纹
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抗层状撕裂
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特厚压力容器板
张玉柱
,
雷云波
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李俊国
,
邢宏伟
,
韩志杰
,
龙跃
钢铁钒钛
采用扫描电子显微镜和化学分析方法对三种不同方式处理的钢渣中f-CaO的显微形貌及含量进行分析研究,试验结果表明,钢渣中弥散型f-CaO主要形成于C2S和C3S初晶、RO相形成和C3S分解等过程,其数量多、分布广、粒径较小;缓冷渣中氧化钙的典型显微形貌为灰色圆粒状、薄膜状、细小长条状;气淬渣中氧化钙的典型显微形貌为灰色薄膜状和细小长条状;热焖渣中氧化钙典型显微形貌为细小长条状;冷却强度对钢渣中f-CaO含量影响显著,因此冷却强度最弱的缓冷渣中f-CaO含量达到了6.96%,而冷却强度最高、经过水解的热焖渣中f-CaO含量只有0.55%;前期冷却强度高、后期冷却强度弱的气淬渣中f-CaO含量为2.28%;降低气淬钢渣粒径,可降低渣中f-CaO含量,从而提高其综合利用价值.
关键词:
钢渣
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冷却强度
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自由氧化钙
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显微形貌
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缓冷渣
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气淬渣
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热焖渣
李辉
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史诗
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冯绍航
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沈宝镜
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张巨清
硅酸盐通报
本文采取加消解剂、磨细、加分散剂三种方式组合对用循环流化床锅炉低温烧成的高钙粉煤灰进行处理,以消解其中的f-CaO.分析按不同方式处理后高钙粉煤灰中f-CaO的含量,并利用扫描电镜观察f-CaO消解后的形貌变化.试验结果表明:未添加分散剂条件下,消解剂量对f-CaO消解的影响最大,其次为粉磨时间,最后为消解时间;添加分散剂有助于水分由粉煤灰颗粒表面孔隙进入其内部,加快f-CaO消解.扫描电镜观察显示仅加消解剂处理高钙粉煤灰中的f-CaO消解后生成了呈六方片状、板状和短柱状的Ca(OH)_2;而加消解剂同时加入分散剂,不光在高钙粉煤灰颗粒表面,在其内部也生成大量簇状的Ca(OH)_2.
关键词:
高钙粉煤灰
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f-CaO消解
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消解剂
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粉磨
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分散剂