Lee Sung Yong, Park Ki Beom, Kang Jang-Won, Kim Yanghoo, Kang Hyun-Su, Ha Tae Kwon, Min Seok-Hong, Park Hyung-Ki
Gangwon Regional Division, Korea Institute of Industrial Technology, Gangneung 25440, Korea.
Department of Advanced Metal and Materials Engineering, Gangneung-Wonju National University, Gangneung 25457, Korea.
Materials (Basel). 2019 Oct 29;12(21):3549. doi: 10.3390/ma12213549.
In this study, the sintering behaviors of Nb-6Mo-20Si-3Cr (at percentage) in situ composite powders were studied. The Nb alloy powder was fabricated by a hydrogenation-dehydrogenation method, and both the alloy ingot and powders consisted of two phases: An Nb metal phase and the α-NbSi phase. Consolidation of the alloy powders was performed at 1500, 1600, and 1700 °C using spark plasma sintering, and the microstructures and phases formed at various sintering temperatures were analyzed. Micropores were observed in the compact sintered at 1500 °C due to the lack of complete densification at that temperature. The densification was completed at 1600 °C and the microstructure was slightly coarsened at 1700 °C compared to the microstructure of the compact sintered at 1600 °C. The microstructures prepared by the powder metallurgy method were finer than the microstructure of the ingot prepared by the casting method. The phase formation behavior varied according to the sintering temperature. Specifically, the α-NbSi phase, which is a stable structure of the NbSi phase at a low temperature, was transformed to the β-NbSi phase (which is stable at a high temperature) with an increasing sintering temperature.
在本研究中，对Nb-6Mo-20Si-3Cr（原子百分比）原位复合粉末的烧结行为进行了研究。铌合金粉末采用氢化-脱氢法制备，合金铸锭和粉末均由两相组成：铌金属相和α-NbSi相。使用放电等离子烧结在1500、1600和1700℃下对合金粉末进行固结，并分析了在不同烧结温度下形成的微观结构和相。由于在1500℃时缺乏完全致密化，在该温度下烧结的坯块中观察到微孔。在1600℃时致密化完成，与在1600℃烧结的坯块的微观结构相比，在1700℃时微观结构略有粗化。通过粉末冶金法制备的微观结构比通过铸造法制备的铸锭的微观结构更细。相形成行为随烧结温度而变化。具体而言，α-NbSi相是NbSi相在低温下的稳定结构，随着烧结温度的升高，转变为β-NbSi相（在高温下稳定）。
