TiH_(2)粉末烧结研究进展

Research Progress in Powder Sintering of TiH_(2)

目的研究烧结温度、升温速率、压制压力分别对TiH2粉末压坯脱氢相演变过程以及显微组织的影响规律。方法采用氢化钛(TiH2)粉末为原料,经过压制和真空烧结制备粉末冶金Ti材料,结合原位中子粉末衍射、差示扫描量热法等技术,表征TiH2粉末压坯在烧结过程中的显微形貌及相变过程。结果在真空烧结条件下,TiH2粉末压坯的脱氢相变反应过程为:δ-Ti(H)→δ-Ti(H)+α-Ti(H)→δ-Ti(H)+β-Ti(H)+α-Ti(H)→β-Ti(H)+α-Ti(H)+α-Ti→α-Ti;升温速率的增加会延缓TiH2的相变过程及动力学。结论TiH2粉末坯体的压制压力越大,烧结时TiH2脱氢并释放氢气导致坯体内部的气压越高,从而导致TiH2坯体的烧结致密化程度较低。

The work aims to investigate the effects of sintering temperature,heating rate,and compaction pressure on the dehydrogenation and microstructure of TiH2 powder sintering.With TiH2 as raw material,powder metallurgy Ti material was prepared by compaction and vacuum sintering.In-situ neutron diffraction and differential scanning calorimetry were employed to characterize the micro appearance and phase transformation of TiH2 powder compacts during vacuum sintering.The results showed that the in-situ phase transformation during vacuum sintering of the TiH2 powder compact was as the following sequence:δ-Ti(H)→δ-Ti(H)+α-Ti(H)→δ-Ti(H)+β-Ti(H)+α-Ti(H)→β-Ti(H)+α-Ti(H)+α-Ti→α-Ti.Moreover,a higher heating rate also delayed its phase transformation procedure as well as kinetics.Besides,dehydrogenation of TiH2 causes the release of H2 gas.In this case,if the compaction pressure is larger,thus the gas pressure due to the H2 release inside the powder compact is higher,yielding a relatively lower densification degree for the TiH2 powder compact.