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31.
<正> 文献[1]曾对金属玻璃(Fe_(1-x)Co_x),_(78)Si_(10)B_(12)的晶化,作过X射线衍射和透射电镜研究,指出初期晶化相为相应晶态Fe_(1-x)Co_x的室温平衡相.本工作将在验证这一结论的基础上,研究初期晶化对一定磁场强度下磁化强度(定场磁化)的影响。 一、样品和实验方法 成分为(Fe_(1-x)Co_x)_(78)Si_(10)B_(12)(x=0.1,0.5,0.7,1)的合金用单辊快淬法制成截面为~1×0.3mm的金属玻璃窄带,用示差扫描热分析法测定其晶化温度T_(cr)(升温速率10℃/min)分别为505,490,440和420℃.磁性试样在石英管式炉中依次进行退火,退火温度T_a=350-500℃,除了x=0.7的样品在T_a≥450℃退火10min外,T_a≤450℃退火20min, 相似文献
32.
带钢表面振纹的工业试验与发现 总被引:31,自引:0,他引:31
对某平整机生产的带钢表面横振纹进行了一系列试验研究 ,发现带钢表面振纹与系统的自激振动强相关 ,此种振动源于部分流体润滑与粘滑兼存的辊缝界面 相似文献
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用粉末冶金工艺制备了Sm(CobalFexCu0.88Zr0.025)7.5(x=0-0.30)烧结磁体,对Fe含量x对磁体的磁性及其高温特性的影响进行了系统研究.随Fe含量的增加,最大磁能积(BH)max和剩磁Br逐渐增加,分别在x为0.21和0.27时达到了最大值205kJ/m3和1.055T,然后迅速下降.当x≥0.24时,磁体中开始有FeCo软磁性相析出,破坏了磁体的永磁特性.Fe含量对磁体高温稳定性有巨大的影响,在Fe含量x=0.21时,磁体内禀矫顽力温度系数β为-0.23%/K;当x=0.07时,β降至-0.14%/K(293-723K).制备出有很好的高温稳定性的永磁材料Sm(CobalFe0.07Cu0.088Zr0.025)7.5,在723K时其磁性能为:Br=0.725T,bHc=517kA/m,iHc=764kA/m,(BH)max=95 kJ/m3,B-H退磁曲线保持为直线. 相似文献
35.
XIAN Aiping LI Peiji CHEN Wenxiu WANG Yikang Institute of Metal Research Academia Sinica Shenyang ChinaCHEN Renvi MEI Dongsheng Panzhihua Institute of Iron Steel Research Ministry of Metallurgical Industry Panzhihua China associate professor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1993,6(6):415-419
The determination of dffusible hydrogen in U71Mn heavy rail steel,and hydrogen diffusivityas well as the hydrogen distribution in the cross section of blooms with stack cooling were stu-died.The results showed that,most of the hydrogen in blooms of heavv rail steel is diffusible,the hydrogen diffusivity in U71Mn rail steel blooms at room temperature is(0.85—1.02)×10~(-6)cm~2/s,after stack cooling,the hydrogen content in bloom will decrease greatly which ishelpful to form the flake-free phenomenon in the heavy rail produced by Panzhihua Iron andSteel Company. 相似文献
36.
A number of coal blends and pitch/coal blends were evaluated using rheometry, thermogravimetric analysis and microscopy to confirm and further elucidate the coking pressure mechanism previously proposed by Duffy et al. (2007) [1]. We confirm that blending a low rank, high fluidity, low coking pressure coal, with a high rank, low fluidity, high coking pressure coal can significantly reduce the coking pressure associated with the latter. Interestingly, blending does not necessarily result in a fluidity that is midway between that of the two coals; sometimes the fluidity of the blend is less than that of the low fluidity coal, especially when the coals are significantly different in rank. This occurs because the increase in complex viscosity (η*) through resolidification of the low rank, high fluidity coal counteracts the reduction in η* resulting from softening of the high rank, low fluidity coal. It has also been confirmed that the η* of the resultant blend can be estimated from the η* of each component coal using a logarithmic additivity rule commonly employed for polymer blends.Polarised light microscopy has indicated that the degree of mixing between coals of different rank is minimal, with fusion restricted to the particle surface. It is therefore inappropriate to think of such a coal blend in the same way as a single coal, since each component coal behaves relatively independently. This limited fusion is important for understanding the coking pressure mechanism for blends. It is proposed here that the lower rank coal, which softens at lower temperature, is able to expand into the interparticle voids between the high rank coal that is yet to soften, and these voids can create channels for volatiles to traverse. Then, and importantly, when the high rank coal begins to expand, the pore structure developed in the resolidified structures of the low rank coal can facilitate removal of volatiles, while the resolidified material may also act as a suitable sorbent for volatile matter. This is considered to be the primary mechanism by which coal blending is able to alleviate coking pressure, and applies to addition of inert material also.Addition of a coal tar pitch was found to increase fluidity but also to extend the thermoplastic range to lower temperatures. This caused an increase in the swelling range, which was accompanied by a long plateau in η*, a feature which has previously been observed for certain high fluidity, high pressure coals. Elasticity and η* at the onset of expansion were also higher for both the pitch impregnated coals and the high pressure blends, which supports previous findings for singly charged high pressure coals, and confirms the potential use of such criteria for identifying potentially dangerous coals/blends. 相似文献
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通过天然径流演变对河流生态系统和生态条件进行定量分析是目前河流生态学领域的重要研究手段之一.本研究采用长江宜昌站1978年-1991年实测日径流资料,从中提取径流演变统计特征量,利用主成分分析方法对统计特征量进行降维,通过对流量机制特征量主成分与长江中下游各省水产业总产量及其增长率的回归分析,发现:径流演变特征值与水产业总产量之间显著相关,径流演变特征值与水产业增长率存在显著的滞后性相关关系.研究结果表明:长江上游径流演变对于中下游河流生态系统的维持和发展有重要意义. 相似文献
39.
Nelly Abigail Rodríguez Efrain Almanza María de Jesús Pérez Carlos Rodrigo Mu?iz Scott Packer Russell Steel 《Frontiers of Materials Science in China》2010,4(4):415-419
This study evaluates the degree of sensitization (DOS) of 304 stainless steel joined by friction stir welding (FSW). Single-loop
electrochemical potentiokinetic reactivation tests were performed using a 0.5 mol/L H2SO4 + 0.01 mol/L KSCN solution. Sensitization was promoted by exposition of the stainless steel at temperatures between 400°C
and 850°C. The microstructure was characterized using optical microscopy to identify the weld zone and the base metal. The
samples treated at 550°C showed the most severe intergranular corrosion. The DOS was lower in the weld zone than in the base
metal after heat treatments. This reduction in the DOS for the weld zone indicates that FSW is a beneficial process in joining
stainless steel. 相似文献
40.
LIU KaiHuang LIU TianCheng LI JianLiang ZHANG Liang ZHANG HongHao LI DeRen LU ZhiChao & ZHOU ShaoXiong China Iron Steel Research Institute Beijing China Advanced Technology Materials Co. Ltd. 《中国科学:信息科学(英文版)》2010,(4)
A composite consisting of flake-shaped Fe74Cr2Mo2Sn2P10Si4B4C2 particles was prepared.The flake-shaped particles included in the composite were prepared by planetary ball milling.The complex permeability of the composite material was measured at frequency range from 10 MHz to 8.5 GHz.The permeability of the composite containing flake-shaped particles was much higher than that of the spherical particles.The permeability of particles was improved by means of heat-treatment.In contrast to the random-spatial-di... 相似文献