High-temperature strength and plastic deformation behavior of niobium diboride consolidated by spark plasma sintering
High-temperature strength and plastic deformation behavior of niobium diboride consolidated by spark plasma sintering
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DOI：
10.1111/jace.15048
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发表时间：
2017-11
影响因子：
3.9
通讯作者：
D. Demirskyi;I. Solodkyi;T. Nishimura;Y. Sakka;O. Vasylkiv
中科院分区：
文献类型：
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作者：
D. Demirskyi;I. Solodkyi;T. Nishimura;Y. Sakka;O. Vasylkiv
大块二硼化铌陶瓷通过 1900 °C 的放电等离子烧结 (SPS) 进行固结。 SPS 产生的致密样品的密度为理论密度的 98%，平均晶粒尺寸为 6 μm。在 SPS 固结过程中，粉末颗粒表面的 B2O3 和二硼化物粉末中残留的吸附氮形成六方氮化硼 (h-BN)。这些 NbB2 块体的室温强度为 420 MPa。 NbB2 陶瓷的弯曲强度在 1600 °C 之前保持不变。在 1700 °C 时，观察到强度增加至 450 MPa，同时伴随着二次 h-BN 相的消失。最后，在 1800 °C 时观察到塑性变形的迹象。断口分析显示出许多蚀刻坑和阶梯状表面，表明存在高温变形。将 SPS 制备的 NbB2 块体的弯曲强度的温度依赖性与整体 TiB2、HfB2 和 ZrB2 的数据进行了比较。我们的分析表明，SPS 固结过程中积累的热应力可能会导致高温下的额外强化。本文受版权保护。版权所有。
Bulk niobium diboride ceramics were consolidated by spark plasma sintering (SPS) at 1900 °C. SPS resulted in dense specimens with a density of 98% of the theoretical density and a mean grain size of 6 μm. During the SPS consolidation, the hexagonal boron nitride (h-BN) was formed from B2O3 on the powder particle surface and residual adsorbed nitrogen in the raw diboride powder. The room-temperature strength of these NbB2 bulks was 420 MPa. The flexural strength of the NbB2 ceramics remained unchanged up to 1600 °C. At 1700 °C an increase in strength to 450 MPa was observed, which was accompanied by the disappearance of the secondary h-BN phase. Finally, at 1800 °C signs of plastic deformation were observed. Fractographic analysis revealed a number of etching pits and steplike surfaces suggestive of high-temperature deformation. The temperature dependence of the flexural strength of NbB2 bulks prepared by SPS was compared with data for monolithic TiB2, HfB2 and ZrB2. Our analysis suggested that the thermal stresses accumulated during SPS consolidation may lead to additional strengthening at elevated temperatures. This article is protected by copyright. All rights reserved.