论文部分内容阅读
通过磁控溅射法并借助有机高分子牺牲层,制备了具有不同调制结构的自支撑Ti/Al(调制比为1)纳米多层膜.采用脉冲激光诱发了纳米多层膜的自蔓延反应,确定了临界诱发能量密度.利用高速摄影法表征了自蔓延速度,采用SEM和TEM观察了纳米多层膜结构,利用差热分析仪和XRD分析了反应过程及产物.结果表明,纳米多层膜激光诱发临界能量密度(6~17 J/cm2)高于烧蚀临界能量密度.调制周期或周期数较小的纳米多层膜激光诱发所需的能量密度较小且自蔓延速度较高.但当调制周期接近或小于层间原子互溶区厚度时,临界能量密度和自蔓延速度的变化则有相反趋势.对于一定厚度的纳米多层膜,具有大调制周期和小周期数的调制结构对应的放热量大.随激光脉冲持续时间的延长,Ti/Al纳米多层膜的激光临界诱发能量密度呈现递减趋势,但最终趋于稳定.激光诱发Ti/Al纳米多层膜自蔓延反应生成单一的TiAl金属间化合物.
Self-supported Ti / Al multilayers with different modulation structures were prepared by magnetron sputtering and sacrificial layer of organic polymer.The self-propagating reaction of nano-multilayers was induced by pulsed laser , The critical induced energy density was determined.The self-propagating velocity was characterized by high-speed photographic method, the structure of the nanometer multi-layer film was observed by SEM and TEM, the reaction process and the product were analyzed by differential thermal analyzer and XRD.The results showed that nano- The laser induced critical energy density (6-17 J / cm2) is higher than the critical energy density of ablation, and the energy density and the self-propagating rate required for laser induced thin film nanostructures are smaller. However, when the modulation period is close to or less than the thickness of the intermetallic atoms, the variation of the critical energy density and the self-propagating velocity have the opposite trend. For a certain thickness of the nano-multilayer, the modulation structure with large modulation period and small period corresponds to With the increase of laser pulse duration, the critical laser induced energy density of Ti / Al nano-multilayers showed a decreasing trend but eventually stabilized.Laser-induced Ti / Al nano-multilayers from Casting the TiAl intermetallic compound single reaction.