Change in relative density of WC-Co cemented carbides in spark plasma sintering process

The relative density of WC-Co cemented carbides during spark plasma sintering（SPS） was analyzed.Based on the change in displacement of the ram in the SPS system,the relative densities in the sintering process can be achieved at different temperatures.The results indicated that densification of the samples started at near 900°C,the density rapidly reached its maximum at the increasing temperature stage,in which the temperature was lower than the sintering temperature of 1200°C,and most of the densification took place in the stage.Besides,the theoretical values were consistent with the experimental results.

Enhanced Electronic Raman Spectra of Different Morphologic Neodymium Hydroxides

Nd（OH）3 particles sized of nanometer have been prepared using the different methods. The obtained neodymium hydroxide samples were investigated using the enhanced electronic Raman spectroscopy, Xray diffraction, transmission electron microscopy, as well as field emission electron microscopy. Observable changes in electronic Raman bands were found among the electronic Raman spectra of Nd （OH）3 particles which formed under different physical-chemical conditions. Compared to the difference of the X-ray diffraction paterns, it suggests that the change of size and morphology of Nd （OH）3 particles occurs with subtle variation on dae coordination environment around the neodymium ions,

应用微计算机断层扫描技术评估C57/B6小鼠生长不同时期髋关节发育

发育性髋关节发育不良受遗传因素影响,患者髋臼容积较正常人小[1-2]。C57/B6小鼠与人类基因组相似率高达99%,是研究遗传性疾病的有效动物模型,但目前未有评估其髋关节的方法。本研究通过计算机断层扫描技术(MicroCT)测量得到髋连续横断面图像,准确测量小鼠各时期髋臼容积(AV),股骨头体积(FHV)及相关参数。

不同状态V-5Cr-5Ti合金的拉伸性能及其强化机制研究

通过对热锻开坯后V-5Cr-5Ti合金开展冷轧变形和热处理实验,利用万能试验机、扫描电镜(SEM)和透射电镜(TEM)研究了V-5Cr-5Ti合金的拉伸性能及其强化机制。结果表明:V-5Cr-5Ti合金冷变形后,位错密度急剧增加,合金在拉伸应力-应变曲线中屈服现象消失,1000℃×1 h热处理后,由于位错受到气团的钉扎作用产生明显的屈服现象。冷变形后V-5Cr-5Ti合金的屈强比急剧升高,变形量为40%时,合金的屈强比为0.99。1000℃×1 h热处理后合金屈强比上升缓慢,当变形量为80%时,合金的屈强比显著升高,由0.70上升到0.79,其中80%冷变形V-5Cr-5Ti合金退火热处理后抗拉强度、屈服强度和延伸率平均值分别为487.3 MPa,382.7 MPa和26.2%。V-5Cr-5Ti合金在冷变形过程中,位错增殖迅速,强度急剧升高,合金强化机制以形变强化为主;1000℃×1 h热处理后,合金发生再结晶转变,形变强化效果消失,合金强化机制以细晶强化和第二相强化为主。