不同配系自反应喷射成形复相陶瓷坯件的组织与性能

Research on structure and performances of self-reactive spray formed multiphased ceramic preforms in different systems

  • 摘要: 以化学反应摩尔比配制的Ti-B4C-C(以蔗糖为前驱体)为基础体系, 再分别添加5wt%Al、 5wt%Al+20wt%Al-Ni、 5wt%Al+20wt%Cu-Ni组成4种反应体系, 进行自反应喷射成形Ti(C,N)-TiB2基复相陶瓷坯件试验, 研究比较4种反应体系喷射沉积坯件的组织与性能特点。研究发现, 4种坯件的组织结构均表现为以Ti(Cx, Ny)-TiB2为主相, 以其它产物为副相的特点, 且微/纳米尺度的TiB2棒晶弥散分布在Ti(Cx, Ny)基体相内, 其它副相则不规则地散布于整个坯件之中, 此外坯件内部均不同程度地存在孔隙。Ti-B4C-C-Al体系的喷射沉积坯件硬度最高, 这与其主相所占比重较大并存在Al2O3等硬质相有关; Ti-B4C-C-Al+Cu-Ni体系的喷射沉积坯件的致密度和弯曲强度最低, 这与喷射过程中碳的氧化损失严重, 碳氮化钛中氮含量与其它副产物相增多有关; Ti-B4C-C-Al+Al-Ni体系的喷射沉积坯件的致密度、弯曲强度和断裂韧性最高, 这是由于该坯件内除存在裂纹偏转与裂纹被钉扎外, 还出现了微裂纹增韧机制。

     

    Abstract: Based on the main system of Ti-B4C-C (sucrouse as the precursor of carbon) in mole ratio and with the additives of 5wt%Al, 5wt%Al+20wt%Al-Ni and 5wt%Al+20wt%Cu-Ni, the Ti(C,N)-TiB2 multi-phased ceramic preforms were prepared by self-reactive spray forming technology. And the structure and mechanical performances of the self-reactive spray formed preforms in different systems were contrastively studied. The results show that the four kinds of preforms have the similar structural character, which is composed of the main phases of continuous matrix phase Ti(Cx, Ny), dispersed micro/nanometric rodlike grains TiB2, some by-product phases and a few of pores. The preforms of Ti-B4C-C-Al system have the highest hardness. The preforms of Ti-B4C-C-Al +Cu-Ni system have the lowest density and flexural strength. The preforms of Ti-B4C-C-Al +Al-Ni system have the highest density, flexural and fracture toughness, which is due to the crack deflection and pinning and micro-cracks toughening mechanism.

     

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