Ti_(1.0)Cr_(1.5)V_(1.7)合金的氢同位素效应

Hydrogen Isotope Effects in Ti_(1.0)Cr_(1.5)V_(1.7) Alloy

采用电弧熔炼的方法,制备了Ti_(1.0)Cr_(1.5)V_(1.7)合金。通过SEM、EDS和XRD对合金的形貌、组成及其氢化物的结构进行表征。结果表明,合金组成不均匀,存在网状的析出相。吸氢过程中的相转变只与吸氢量有关,而与氢同位素种类无关。分离因子(aH–D)测试表明,压力对aH–D的影响不大,但氘丰度的增加会导致aH–D的降低。温度对aH–D的影响较复杂。aH–D在213 K时有极大值2.29。当温度高于213 K时,aH–D的实验值与谐振模型的计算值符合得很好,且lnaH–D与1/T之间存在线性关系;当温度低于213 K时,实验值与计算值之间存在较大差异。Ti_(1.0)Cr_(1.5)V_(1.7)合金氢化物的DSC分析结果表明,aH–D在低温时的突变与相转变之间并无直接的联系。

Ti1.0Cr1.5V1.7alloy was prepared by arc melting and then its morphology and constitution were analyzed by SEM and EDS. The observations showed that the alloy was unhomogeneous with some network-shaped precipitates. The structures of the hydrides of Ti1.0Cr1.5V1.7 were determined by XRD. The structures of the hydrides depended only on the hydrogen content, not on the kind of hydrogen isotopes. The dependences of separation factor （αH-D） on pressure, deuterium concentration and temperature were investigated systematically. Not significantly influenced by pressure, αH-D decreased with the increase of deuterium concentration. However, the dependence of αH-D on temperature was complicated. In 213-373 K, αH-D increased with the decrease of temperature, which agreed with the harmonic oscillator model （HOM）. In 77-213 K, the experimental aH-D was different from the calculated value of HOM. According to the results of DSC measurement for the hydrides of V alloy, the disagreement between the experiments and the HOM in 77-213 K was not induced by phase transitions. Moreover, the maximum αH-D reached 2.29 at 213 K.