Wen Feng, Liu Wentao, Fu Ao, Huang Qianli, Wang Jian, Cao Yuankui, Qiu Jingwen, Liu Bin
China North Nuclear Fuel Co., Ltd., Baotou 014035, China.
State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
Materials (Basel). 2024 Aug 22;17(16):4155. doi: 10.3390/ma17164155.
The Nb-16Si-24Ti-2Al-2Cr alloy was prepared by plasma rotating electrode process (PREP) technology and the hot-pressing (HP) method, and the effects of sintering temperature on the microstructure, mechanical properties and fracture behavior were investigated. The HP alloys sintered at temperatures below 1400 °C are composed of Nbss (Nb solid solution), NbSi and NbSi phases. When the sintering temperature reaches 1450 °C, the NbSi phase is completely decomposed into Nbss and NbSi phases. Meanwhile, the microstructure coarsens significantly. Compared with the cast alloy, the HP alloy shows better mechanical properties. The fracture toughness of the alloy sintered at 1400 °C reaches 20.2 MPa·m, which exceeds the application threshold. The main reason for the highest fracture toughness is attributed to the decomposition of large-sized brittle NbSi phase and the formation of a fine microstructure, which greatly increases the number of phase interfaces and improves the chance of crack deflection. In addition, the reduction in the size and content of silicides also reduces their plastic constraints on the ductile Nbss phase.
通过等离子旋转电极工艺（PREP）技术和热压（HP）法制备了Nb-16Si-24Ti-2Al-2Cr合金，并研究了烧结温度对其微观结构、力学性能和断裂行为的影响。在1400℃以下温度烧结的热压合金由Nbss（Nb固溶体）、NbSi和NbSi相组成。当烧结温度达到1450℃时，NbSi相完全分解为Nbss和NbSi相。同时，微观结构显著粗化。与铸造合金相比，热压合金表现出更好的力学性能。在1400℃烧结的合金的断裂韧性达到20.2MPa·m，超过了应用阈值。断裂韧性最高的主要原因是大型脆性NbSi相的分解和精细微观结构的形成，这大大增加了相界面的数量并提高了裂纹偏转的机会。此外，硅化物尺寸和含量的减少也降低了它们对延性Nbss相的塑性约束。
