CHAI Feng
,
YANG Caifu
,
SU Hang
,
ZHANG Yongquan
,
XU Zhou
钢铁研究学报(英文版)
The weldability of a lowcarbon copperbearing age hardening steel was evaluated using cracking susceptibility calculation, HAZ maximum hardness measurement, and Ygroove cracking evaluation test. The results show that the hardenability characteristics and cold cracking susceptibility of the steel are very low. The results also indicate that a crackfree weldment can be obtained during the welding of this type of steel even at an ambient temperature as low as -5 ℃ as well as in an absolute humidity lower than 4 000 Pa without any preheat treatment. A slight preheat treatment can prevent the joint from cracking when welding is carried out at lower ambient temperature or higher absolute humidity.
关键词:
copperbearing age hardening steel;weldability;cracking resistance;Ygroove cracking test
SU Hang
,
PAN Tao
,
LI Li
,
YANG Caifu
,
CUI Yinhui
,
JI Huaizhong
钢铁研究学报(英文版)
By combining thermomechanical coupling finite element analysis with the characteristics of phase transformation [continuous cooling transformation (CCT) curve], the thermal fatigue behavior of train wheel steel under high speed and heavy load conditions was analyzed. The influence of different materials on the formation of the phase transformation zone of the wheel tread was discussed. The result showed that the peak temperature of wheel/track friction zone could be higher than the austenitizing temperature for braking. The depth of the austenitized region could reach a point of 09 mm beneath the wheel tread surface. The supercooled austenite is transformed to a hard and brittle martensite layer during the following rapid cooling process, which may lead to cracking and then spalling on the wheel tread surface. The decrease in carbon contents of the train wheel steel helps inhibit the formation of martensite by increasing the austenitizing temperature of the train wheel steel. When the carbon contents decrease from 07% to 04%, the Ac3 of the wheel steel is increased by 45 ℃, and the thickness of the martensite layer is decreased by 30%, which is helpful in reducing the thermal cycling fatigue of the train wheel tread such as spalling.
关键词:
train wheel steel;thermal cycling fatigue;friction;martensite transformation;thermomechanical coupling
ZHAO Xiqing
,
PAN Tao
,
WANG Qingfeng
,
SU Hang
,
YANG Caifu
,
YANG Qingxiang
钢铁研究学报(英文版)
Mechanical properties of quenching, intercritical quenching and tempering (QLT) treated steel containing Ni of 9% were evaluated from specimens subject to various tempering temperatures. The detailed microstructures of steel containing Ni of 9% at different tempering temperatures were observed by optical microscope (OM) and transmission electron microscope (TEM). The volume fraction of austenite was estimated by XRD. The results show that high strength and cryogenic toughness of steel containing Ni of 9% are obtained when the tempering temperature are between 540 and 580 ℃. The microstructure keeps the dual phase lamellar structure after the intercritical quenching and there is cementite created in the Nirich constituents when tempering temperature is 540 ℃. When tempering temperatures are between 560 and 580 ℃, the reversed austenites (γ′) grow up and the dual phase lamellar structure is not clear. The γ′ becomes instable at 600 ℃. When tempered at temperature ranging from 500 to 520 ℃, the increase of dislocation density in the lamellar matrix makes both tensile strength and yield strength decrease. When tempered at 540 ℃ and higher temperature, the yield strength decreases continuously because the C and alloying elements in the matrix are absorbed by the cementite and the γ′, so the yield ratio is decreased by the γ′. There are two toughness mechanisms at different tempering temperatures. One is that the precipitation of cementite absorbs the carbon in the steel which plays a major role in improving cryogenic toughness at lower temperature. Another is that the γ′ and the purified matrix become major role at higher tempering temperature. When the tempering temperature is 600 ℃, the stability of γ′ is decreased quickly, even the transformation takes place at room temperature, which results in a sharp decrease of CharpyV impact energy at 77 K. The tempering temperature range is enlarged by the special distribution of cementite and the lamellar structure.
关键词:
steel containing Ni of 9%
,
tempering temperature
,
cementite
,
reversed austenite
,
cryogenic toughness
CHAI Feng
,
YANG Caifu
,
SU Hang
,
ZHANG Yongquan
,
XU Zhou
钢铁研究学报(英文版)
Effects of Mg on the chemical component and size distribution of Tibearing inclusions favored grain refinement of the welding induced coarsegrained heat affected zone (CGHAZ), with enhanced impact toughness in Tikilled steels, which were examined based on experimental observations and thermodynamic calculations. The results indicated that the chemical constituents of the inclusions gradually varied from the TiO+TiMgO compound oxide to the TiMgO+MgO compound oxide and the singlephase MgO, as the Mg content increased from 0002 3% to 0006%. A trace addition of Mg (approximately 0002%) led to the refinement of Tibearing inclusions by creating the TiMgO compound oxide and provided favorable size distribution of the inclusions for acicular ferrite transformation with a high nucleation rate in the CGHAZ, and a high volume fraction of acicular ferrite was obtained in the CGHAZ with enhanced impact toughness. Otherwise, a high content of Mg (approximately 0006%) produced a singlephase MgO, which was impotent to nucleate an acicular ferrite, and a microstructure comprised of a ferrite side plate and a grain boundary ferrite developed in the CGHAZ. The experimental results were confirmed by thermodynamic calculations.
关键词:
nonmetallic inclusion;magnesium;acicular ferrite;coarsegrained heat affected zone (CGHAZ)
万小峰
,
张久兴
,
周文元
,
李湘波
,
周美玲
稀有金属材料与工程
研究了FU105大功率广播发射管用碳化镧钼阴极,参照碳化钍钨阴极FU105管的制备工艺,实现了镧钼阴极的碳化以及镧钼阴极FU105管的排气和老炼.通过镧钼阴极FU105管的性能测试,对碳化镧钼阴极的发射能力和稳定性进行了分析.结果认为:FU105管碳化镧钼阴极的发射能力可以达到碳化钍钨阴极的水平,但其稳定性还有待改进.
关键词:
镧钼阴极
,
FU105发射管
,
碳化
,
稀土
钟文远
,
崔永春
,
范春兰
,
胡智兴
,
李玛琳
贵金属
doi:10.3969/j.issn.1004-0676.2004.02.005
为寻求高效低毒的新型顺铂类抗肿瘤药物,用K2PtCl4、乙二胺(en)、氟尿嘧啶(5-Fu)为原料,设计合成了顺铂类似物[pt(en)(5-Fu)2]C12配合物,由元素分析、红外光谱和质谱分析初步证实了其化学结构,用改良MTT、SRB法,选用K562、A549、Bel-7402、BIU-87、Bcap-37细胞株对其进行体外抗肿瘤活性测定.结果表明,所合成的配合物除在浓度为0.01、0.1 μg/mL时对K562细胞株抗肿瘤活性大于顺铂和氟尿嘧啶外,其它情况下的抗肿瘤活性均小于顺铂和氟尿嘧啶.该配合物仍有进一步研究的价值.
关键词:
药学
,
铂(Ⅱ)配合物
,
合成
,
抗肿瘤活性
张宝艳
,
陈祥宝
,
李敏
,
邢丽英
,
汪亮
,
蒋诗才
航空材料学报
doi:10.3969/j.issn.1005-5053.2002.01.008
探讨了树脂基体、碳纤维增强体以及树脂基体-纤维的界面等对双马来酰亚胺(简称双马)树脂基复合材料冲击后压缩强度(CAI)值的影响,指出降低树脂基体的交联密度和产生微观两相结构是提高碳纤维/双马复合材料CAI值的两个典型方法.合适的树脂含量有利于保持复合材料体系较高的CAI值,采用高强高韧性的碳纤维可明显提高复合材料体系的CAI值.为获得较高的CAI值,保持合适的树脂基体-纤维界面性能也是必要的.
关键词:
双马来酰亚胺
,
纤维增强复合材料
,
韧性
,
界面
于跃芹
,
常宪智
,
田红杰
,
许洋
高分子材料科学与工程
选用牛血清蛋白(BSA)和5-氟尿嘧啶(5-FU)为模型药物,以聚天冬氨酸交联温敏性水凝胶为载体材料,采用包埋法制备了载药水凝胶,研究了水凝胶的载药和释药性能.水凝胶对BSA和5-FU的包埋率均大于98%.37℃时,水凝胶中丙烯酸用量越大,BSA的释放率越低;交联剂用量对BSA的释放率无显著影响.25℃时,丙烯酸用量越大,5-FU的释放率越大;交联剂用量越大,5-FU的释放率越小.37℃时,丙烯酸用量越小,5-FU的释放率越大;交联剂用量越大,5-FU的释放率越小.
关键词:
温敏性水凝胶
,
药物缓释
,
5-氟尿嘧啶
,
牛血清蛋白
李和平
,
肖华伍
,
肖子丹
,
阮建明
高分子材料科学与工程
采用交联-聚合法在超声波的作用下,制备了磁性壳聚糖-5-氟尿嘧啶纳米粒(MCN-Fu).透射电子显微镜(TEM) 和红外光谱(IR)等分析结果表明,MCN-Fu粒子外形规整,分散性好,粒径主要在50 nm～60 nm 之间.紫外-可见光谱分析结果表明,MCN-Fu的载药量为21.3%,在磷酸盐缓冲溶液(pH=7.2)中,30 h的累积释药率为67.6%,具有良好缓释性能,并具有良好磁响应性能.
关键词:
磁性
,
壳聚糖
,
氟尿嘧啶
,
纳米粒
,
药物缓释剂
Canying CAI
,
Qibin YANG
,
Hongrong LIU
材料科学技术（英文）
Assuming that the wave function , the Schrodinger equation can be written as . Neglecting the last two terms, an analytical expression of electron dynamical diffraction was derived by Qibin YANG et al. In this paper, the analytical expression is modified by further considering the second-order differential term . When the accelerating voltage is not very high, or the sample is not very thin, the reciprocal vector ɡ is large, the modification of the second-order differential is necessary; otherwise it can be neglected.
关键词:
Electron dynamical diffraction
,
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