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γ(fcc)→α(bcc)马氏体相变表面浮凸的AFM观察与定量分析 总被引:1,自引:1,他引:0
利用原子力显微镜(AFM)及扫描电镜(SEM)观察并定量分析了γ(fcc)→α(bcc)马氏体相变的表面浮凸。结果表明:{259}f马氏体表面浮凸为双倾动、帐篷(∧)型,{557}f马氏体的表达浮凸为“孤立岛状”浮凸群,{225}f马氏体表面浮凸为具有层状结构的“三角形”浮凸群;{259}f马氏体表面浮凸的宽度、高度及浮凸角度均大于{225}f马氏体“三角形”浮凸群,{557}f马氏体表面浮凸群的高度最小,其浮凸角也最小。 相似文献
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采用改进Hummers法制备了氧化石墨烯(GO),使用旋转黏度计测试了掺GO新拌碱矿渣胶结材浆体(AASP)的剪切应力,并基于Herschel-Bulkley(H-B)模型计算了浆体的流变参数,分析了GO对碱矿渣胶结材浆体流变性能的影响.结果表明:GO降低了碱矿渣胶结材浆体的触变性能,提高了浆体的稳定性;GO掺量(质量分数,下同)由0.01%增至0.05%时,碱矿渣胶结材浆体的屈服应力和稠度系数增大、流动度降低、滞回环面积和流变性指数减小、浆体的触变性能降低;GO与矿渣粉颗粒通过化学键合作用生成絮凝结构,且随着GO掺量增加,絮凝结构的数量增多,浆体的流变性能发生变化;掺1.5%萘系减水剂(FDN)可将掺0.03%GO的碱矿渣胶结材浆体流动度由180mm提高到203mm,即掺加FDN可提高含GO碱矿渣胶结材浆体的流动性. 相似文献
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Nanju Gu Huifen Peng Ruixiang Wang 《Metallurgical and Materials Transactions A》1996,27(10):3108-3111
The influence of training temperature on the shape memory effect (SME) for the CuZnAl shape memory alloy (SMA) has been studied.
It is found that there exists an optimum upper training temperature resulting in the best SME which is about 353 K for the
Cu-26Zn-4Al alloy. The preferential oriented martensitic variants will be formed during cooling, since there are aligned dislocations
(resulting in the best two-way memory effect (TWME)) in the parent phase after training between 293 and 353 K. However, the
TWME drops gradually due to the generation of dislocation tangles in the parent phase as the training temperature increases
to 373 K. Further work on the effect of training time on the SME shows that the shift ofA
s temperature is little when alloys studied are trained at the optimum temperature for 15 to 40 seconds and there exists a
certain training time without any shift ofA
s temperature after 1000 thermal cyclings. 相似文献
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7Cr7Mo3V2Si钢加热相变研究 总被引:1,自引:0,他引:1
利用Formastor全自动相变测定仪研究了7Cr7Mo3V2Si钢在连续加热条件下的相变规律及特点;测定了能反映其相变规律与特点的奥氏体形成图。结果表明,钢中球状珠光体向奥氏体的转变是在较宽的温度区间(Ac1b-Ac1e)内完成的;钢中大量合金碳化物的溶解、按其难易程度不同分别与n个溶解温度相对应;连续加热条件下,奥氏体难以实现均匀化。 相似文献
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Huifen PENG Baoqi WANG Jianjun ZHANG Xiaoyan SONG Xiaoli MA Nanju GUSchool of Materials Science & Engineering Hebei University of Techonology Tianjin China 《材料科学技术学报》2004,20(5):567-570
In this research, we tried to find a simple processing method to break up the network carbides in ultrahigh carbon steels (UHCS). Our results revealed that Al addition was favorable to the decrease in the proeutectoid carbides, the pearlite-colony size and the pearlitic interlamellar spacing of the forged microstructures, and that a fully-pearlitic structure was obtained in the UHCS containing 1.6 wt pct Al. The quenching-and-tempering process resulted in fine microstructure in those steels. On the other hand, the strength of the UHCSs increased with the increase of the Al content, and the highest strength was obtained at the UHCS with 1.6 wt pct Al. The UHCSs with Al contents higher than 1.3 wt pct showed a high tensile strength of more than δb=1000 MPa and good ductility of higher than δ5=10% at ambient temperature. 相似文献
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