张进之
,
李生智
,
王廷溥
金属学报
国内外轧制中厚板操作经验是采用“中凸法”(或“中厚法”)轧制,以保证轧制过程的稳定,但按现有理论公式计算所得为保证轧制稳定的“中厚值”太大,影响钢板质量和成材率的提高本文给出了新的板凸度(中厚值)和轧制时轧辊凹度计算公式,经生产实践数据验证表明具有更好的实用性。
关键词:
中厚板
,
rolling
,
stability
,
crown
李力成
,
王昌松
,
马璇璇
,
杨祝红
,
陆小华
催化学报
doi:10.1016/S1872-2067(11)60471-3
An Au-Cu bimetal catalyst was prepared by deposition-precipitation (urea) of gold and copper species on mesoporous TiO2 and activation with H2. The sample was characterized by N2 adsorption/desorption, X-ray diffraction, ultraviolet-visible spectroscopy, and high-resolution transmission electron microscopy. The results showed that the Au and Cu species formed an Au-Cu alloy and were well dis-persed on the mesoporous TiO2. According to CO oxidation test results, it was found that the catalytic activity of gold was enhanced by cop-per. The Au-Cu bimetal catalyst supported on mesoporous TiO2 showed better catalytic stability in CO oxidation than the Au catalyst sup-ported on mesoporous TiO2 and the nonporous TiO2-supported catalysts. This may be related to the effects of both Au-Cu alloying and the mesostructure of TiO2.
关键词:
gold
,
copper
,
mesoporous titania
,
stability
,
carbon monoxide
,
oxidation
裴明哲
,
孙利军
物理测试
用600 ℃时效微观组织变化和冲击韧性的变化评价了1Cr21Ni5Ti双相不锈钢的稳定性。结果表明：1Cr21Ni5Ti双相不锈钢稳定性对Ti/C 极为敏感，低Ti/C（Ti/C=4.08）钢600 ℃时效快速析出富Cr的M23C6碳化物，降低奥氏体内的Cr和C含量致使时效后冷却过程中奥氏体转变为马氏体，并伴随着冲击韧性的严重恶化；而Ti/C适度的钢明显抑制了M23C6碳化物的析出和随后奥氏体向马氏体转变，长时间时效后冲击韧性高出低Ti/C钢近一倍。
关键词:
1Cr21Ni5Ti钢
,
aging
,
stability
,
impact energy
吕铮
,
卢晨阳
,
张守辉
,
谢锐
,
刘春明
金属学报
doi:10.3724/SP.J.1037.2012.00072
采用机械合金化和热等静压技术制备纳米结构14Cr-ODS铁素体钢, 利用SEM, XRD和EDS等手段分析了机械合金化过程中粉末形态和结构的变化以及合金元素的固溶情况, 通过TEM研究了14Cr-ODS铁素体钢的微观结构及其在短时高温下的稳定性. 结果表明, 元素粉末经机械合金化过程中发生反复的冷焊和断裂导致粉末尺寸先增加(0--2 h)后下降 (2-70 h), 晶粒尺寸随球磨时间的增加而减小, 同时Cr, W和Y2O3等固溶入Fe基体中. 纳米结构14Cr-ODS钢中存在3种析出相: 极高密度的、尺寸在几个纳米的富Y-Ti-O团簇, 少量Y2Ti2O7析出相和块状富Cr-Ti相. 经1250 ℃, 8 h短时高温热处理后, 纳米团簇显示出了良好的稳定性, Y2Ti2O7相的密度增加.
关键词:
ODS钢
,
mechanical alloying
,
hot isostatic pressing
,
Y-Ti-O-rich cluster
,
stability
Xiongjian ZHANG
,
Qin HAN
材料科学技术（英文）
The thermal stability of α-Fe2O3 and γ-Fe2O3 nanowires was studied by post annealing the samples at different temperatures. Before and after annealing, the samples were characterized by X-ray diffraction and scanning electron microscopy. The α-Fe2O3 nanowires are stable at the temperatures up to 600℃, and the crystalline structure becomes more perfect after annealing. This behavior supplies a way to improve the quality of the α-Fe2O3 nanowires. The γ-Fe2O3 nanowires become unstable when annealed at 350℃. Raman spectra of both nanowires have been measured, which also indicate that the γ-Fe2O3 nanowires are transformed into α-Fe2O3 under the strong laser beam.
关键词:
Fe2O3 nanowire
,
nanowire
,
Thermal
,
stability
,
Structu
ZHANG Cheng HU Zhuangqi GE Yunlong WANG Yongzhong QIAO Guiwen Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China doctorate student Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The Bi_2(Sr,Ca)_3Cu_2O_x system superconductor was prepared by different melting procedures and after treatment.The effects of cooling rate,annealing temperature and time,as well as melting procedures on phase transformation were investigated.The structure and properties were examined by X-ray diffraction,optical microscopy,EPMA,DTA,TGA and measurements of electric and magnetic properties.When the melt of nominal composition Bi_2(Sr,Ca)_3Cu_2O_x solidified in air,the Bi_2(Sr,Ca)_3Cu_2O_(8+δ)(2212)superconducting phase is stable,the easily solidified product including Bi_2(Sr,Ca)_2CuO_(6+δ)(2201)phase is metastable, and another may be amorphous if rapidly quenched.The last two may transform into 2212 phase by after treatment at an optimal annealing temperature ranging 780—870℃.While 2201 phase,prepared by the laser floating zone melting method,may easily transform into 2212 phase at layer or filament in shape which is favourable to improve the links among superconducting grains and critical current density.
关键词:
Bi system superconductor
,
null
,
null
,
null
T.Yu
,
D.S.Wang
,
D.Wu
金属学报(英文版)
The hysteresis loop changes of ferroelecric SrBi2 Ta2 O9 (SBT) thin films (330nm) vsthe temperature of forming gas (5%o hydrogen+95%o nitrogen) annealing were measuredwhen the annealing time was 1min and 10min. The selected annealing temperaturewas at 100℃, 200℃, 250℃, 300℃, 350℃, 400℃ and 4S0℃, respectively. Our resultsshowed that the ferroelectric properties were easily destroyed and the leakage currentchanged abruptly when the SBT thin films were in their ferroelectric phase (＜270℃).The space charges at the grain boundary may take an important role in absorptionpolarity molecular hydrogen when the SBT thin films were in the ferroelectric phase.The oxygen recovery experiments were also performed and investigated in this work.
关键词:
ferroelectric
,
null
,
null
,
null
