M. J Li
,
G.S. Song
,
G.C. Yang and YH Zhou (State Key Laboratory of Solidification Processing
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)
金属学报(英文版)
Fe-30at.%Co alloy is undereooled to investigate the effct of remelting on the grain size at certain undereooling rnnges. At low undereoolings, the primary stable fcc phase is remelted, which results in the equiaxed grains. When the melt is undercooled greater than the critical undereooling △T=204K the primary metastable bcc phase will alternatively nucleate in the melt. The primary bcc dendrite will be remelted into isolated dendrite cores dispersing in the remaining liquids. In the meanwhile, the isolated dendrite cores are remelted more or less due to the temperature fluctuation in the liquids. Different crystal structures between bcc and fcc phase make the subsequent crystal growth of fcc phase onto the Primary bcc phase non-epitaxial when the melt is undereooled greater than △T=204K. The primary metastable bcc phase may play an important role in coarsening grains in the systetn at larpe undereoolings.
关键词:
undercooling
,
null
,
null
,
null
王炼石
,
周奕雨
,
夏新江
高分子材料科学与工程
测定了SBR-g-S的接枝率,用TEM检测了粉末SBR-g-S(PR)的相结构.用DSC测定了PS/PR共混体的Tg,研究了PS/PR共混体的相容性.结果发现,在接枝率为32.6%的粉末非交联SBR-g-S(PR1)的相结构中SBR为连续相,在连续相中均匀分布着直径约0.01 μm的PS微区;PS为细胞状分散相,粒径1～5 μm,分散相含有SBR包藏物.在接枝率为8.5%的粉末交联SBR-g-S(PR2)的相结构中PS为连续相,SBR为分散相,分散相粒径约0.3 μm.共混体PS/PR1的相容性优于PS/PR2.SBR在PS富相中有较高的含量是导致PS/PR1共混体在冲击断裂时发生剪切屈服的主要原因.
关键词:
粉末SBR-g-S
,
相结构
,
PS/粉末SBR-g-S
,
共混体
,
相容性
卢绍杰
,
刘瑞贤
,
孙希明
,
卫乃勤
,
杨光中
高分子材料科学与工程
以K2S2O8为引发剂,研究了在反相乳液中合成淀粉接枝聚丙烯酰胺共聚物(S-g-PAM),实验证明,加入少量铈离子组成复合体系,对提高反应速率、接枝率和接枝效率起到显著的促进作用.文中对硫酸铈-过硫酸钾(CS-KPS)体系的用量及反应影响因素进行了探讨.
关键词:
淀粉接枝
,
丙烯酰胺
,
复合引发体系
,
反相胶乳
黄治军
,
王玉涛
,
胡家国
钢铁研究
为提高气保焊丝的焊接工艺性能,选用不同化学成分的ER70S-G焊丝进行焊接工艺试验。当焊丝含某种元素X质量分数为0.09%、w（Mn）为1.50%及w（Si）为1.0%时,CO2气体保护焊接飞溅极少,但焊缝宽高比较小,为3.5;当焊丝含某种元素X质量分数为0.01%、w（Mn）为1.70%及w（Si）为0.8%时,CO2气体保护焊接飞溅较少,焊缝宽高比较大,为4.5,显示出很好的焊接工艺性能。结果表明,焊丝的成分对气保焊缝的成形有很大的影响,在某种元素X质量分数、w（Ti）及w（Si）/w（Mn）比适当时,可得到焊接飞溅小、焊缝成形佳的焊接工艺性能。
关键词:
ER70S-G
,
气保焊
,
飞溅
,
成形
刘善喜
,
张彩军
,
吕达
,
马德刚
,
李硕
钢铁钒钛
doi:10.7513/j.issn.1004-7638.2016.05.008
为开发含钛焊丝钢ER70S-G,对其冶炼过程中夹杂的数量、尺寸和类型进行研究.研究发现:在精炼过程中,钢中当量直径夹杂物的数目呈现逐渐降低的趋势;到中间包时,当量直径(5μm)夹杂物数目已经从包样的19.78个/mm2减少到1.66个/mm2;精炼过程夹杂物的平均直径呈逐渐降低的趋势,平均直径为2.05 μm;精炼初期,钢中夹杂物类型主要是MnO-SiO2夹杂,到加钛铁前,钢中的主要夹杂物转变为CaO和MgO,从加钛铁后到中间包期间,Al2O3-Ti2O3-MgO系夹杂是钢中的主要夹杂物.
关键词:
含钛焊丝钢
,
夹杂物
,
数量
,
尺寸
,
类型
材料科学技术（英）
Sulfide stress corrosion cracking (SSCC) behaviour of UNS G11180 steel in 5% NaCl solution with H2S was, studied by slow strain rate tensile test (SSRT), SEM and electrochemical hydrogen permeation technique. The results reveal different cracking mechanism and H permeation current (I-H) through UNS G11180 steel plate in different concentration of H2S solution. The susceptibility to SSCC of UNS G11180 steel in 5% NaCl solution with H2S was evaluated by the permeation current (I-H, mu A), which depends on the concentration (c x 10(-6)) of H2S by the equation: I-H = 8.525 x c(0.7249). It is proved that the electrochemical H permeation method is a practical way to assess the susceptibility to SSCC.
关键词:
cracking
Xueyuan ZHANG and Yuanlong DU(State Key Lab. for Corrosion and Protection
,
Institute of Corrosion and Protection of Metals
,
Chinese Academy of Sciences
,
Shenyang 110015
,
China)
材料科学技术（英）
Sulfide stress corrosion cracking (SSCC) behaviour of UNS G11180 steel in 5% NaCl solution with H2S was studied by slow strain rate tensile test (SSRT), SEM and electrochemical hydro gen permeation technique. The results reveal different cracking mechanism and H permeation current (IH) through UNS G11180 steel plate in different concentration of H2S solution. The susceptibility to SSCC of UNS G11180 Steel in 5% NaCl solution with H2S was evaluated by the permeation current(IH, μA), which depends on the concentration (c×10-6) of H2S by the equation:IH = 8.525 ×c0.7249. lt is proved that the electrochemical H permeation method is a practical way to assess the susceptibility to SSCC.
关键词:
Physica B-Condensed Matter
By extending the theory of Abragam and Pryce, the formulas of EPR parameters g and g(perpendicular to) for 3d(7) ion in trigonal octahedral crystals are established from a cluster approach. In these formulas, not only the configuration interaction effect, but also the covalency effect are considered and the parameters related to both effects and the trigonal distortion are determined from the optical spectra and the structural data of the crystal under study. Based on these formulas, the g(parallel to) and g(perpendicular to) of Cd2P2S6: Co2+ crystal are reasonably explained from its structural data. The relationship between the sign of Deltag (= g(parallel to) - g(perpendicular to)) and the trigonal distortion (elongated or compressed) of ligand octahedron, which is opposite to that obtained in the previous paper, is given and the results are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.
关键词:
electron paramagnetic resonance;crystal- and ligand-field theory;trigonal distortion;Co2+;Cd2P2S6;superposition model;transition;complexes;ion
王炼石
,
周奕雨
,
蔡彤旻
高分子材料科学与工程
以粉末SBR-g-s与PS树脂共混,测定了共混体的Charpy无缺口冲击强度与PR用量的关系曲线.用TEM和SEM分别分析了共混体的相结构和冲击断面形貌.研究了共混体的相结构、冲击断裂机理和冲击强度之间的关系.结果发现,在关系曲线被转变点划分的每一区域内,冲击断裂机理只发生量变而无质变,故冲击强度与PR用量成正比,而随着区域的变换冲击断裂机理发生了质变,导致了冲击强度的变化不连续,从而出现转变点.当粉末非交联SBR-g-s用量为20%,共混体发生脆韧转变;其冲击断面局部区域呈"须根"形貌,证实存在剪切屈服机理;脆韧转变的临界条件为:橡胶相粒径≥0.8 μm,粒面间距离≤0.9 μm,PS富相含混溶性SBR(SBR/PS,质量)≥3%.
关键词:
PS/粉末SBR-g-s共混体
,
冲击强度
,
冲击断裂机理
,
相结构
,
剪切屈服机理
