高级检索

配料及制备工艺对TZC钼合金微观构成的影响

The influence of ingredient and preparation process on the microstructure of TZC molybdenum alloy

  • 摘要: 采用TiH2/ZrH2和TiC/ZrC两种掺杂方式分别在不同的烧结和热压工艺下制备了TZC合金。通过光学金相观察、扫描电子显微分析、物相分析等方式,研究了不同工艺处理的合金微观组织和成分分布的演化。结果表明,两种添加方式的物相构成基本相同,但烧结后添加TiC/ZrC较添加TiH2/ZrH2的TZC合金,密度由9.21 g·cm-3提高到9.68 g·cm-3,合金硬度由210 HV提高到245 HV。烧结后热压使得合金致密度和硬度明显提高,晶粒也由烧结态的双峰型分布转变到单峰型分布。研究发现,两种添加物在高温烧结过程其构成都发生了转变,其反应扩散过程决定了其微观结构,从而决定了其密度和硬度的变化。添加TiH2/ZrH2的合金,经过热压后的微观组织会形成不同的特征区域。添加TiC/ZrC的合金可通过直接热压成形,从而获得晶粒细小,致密度及硬度优良的TZC合金。

     

    Abstract: Different sintering and hot-pressing processes are employed to prepare the TZC alloy with two doping methods of TiH2/ZrH2 and TiC/ZrC addition, respectively. The evolution of the microstructure and composition distribution of the alloy under different processing conditions was studied through optical metallographic observation, scanning electron microscopy analysis and phase analysis. The results show that the phase constituents of the two doping methods are basically the same, but in comparison with that for the alloy with TiH2/ZrH2 addition, the density for the alloy with TiC/ZrC addition after sintering increases from 9.21 g·cm-3 to 9.68 g·cm-3, and the hardness increases from 210 HV to 245HV, respectively. Hot pressing after sintering significantly increases the density and hardness of the alloy, and the grain distribution changes from a bimodal distribution in the sintered state to a unimodal distribution. It is found that the phase structures of the two kinds of additives undergo transformation during high-temperature sintering, of which determines the reaction diffusion process, thereby affects the changes in density and hardness. The alloy with TiH2/ZrH2 addition forms different characteristic regions in the microstructure after hot pressing. Fine-grained, dense, and high-hardness TZC alloy can be directly obtained by hot-pressing the alloy with TiC/ZrC addition.

     

/

返回文章
返回