论文标题
高温稳定的耐火性高渗透纳米合金具有增强性
High-temperature stable refractory high-entropy nanoalloys with enhanced sinterability
论文作者
论文摘要
纳米晶合金（纳米合金）容易出现谷物生长。众所周知，晶界隔离和降水可以稳定纳米合金，但是在高温下稳定效果降低，并增加晶粒生长抑制剂通常会降低易烧结性。在本文中，我们同时实现了一类基于monbtatiw的难治性高渗透纳米合金（RHENS）的改善性和出色的高温稳定性。通过行星球铣削和火花等离子体烧结，制造了大块rhens的块状颗粒，可实现93-96％的相对密度，三个组合物具有50-100 nm的晶粒尺寸。例如，MO17.8NB17.8TA17.8TI17.8W17.8NI6ZR5在1300°C下烧结，相对密度的相对密度约为96％，平均晶粒尺寸约为55 nm。此外，这些RHEN在1300°C下表现出非凡的稳定性。两位TI17.8NB17.8MO17.8TA17.8W17.8NI6ZR5和MO18.8NB18.8TA18.8TI18.8TI18.8W18.8NI6保留了<150 nm的粒度，在1300小时后，在1300小时内，> 96％的理论浓度> 96％的粒度。值得注意的是，添加Ni是一种众所周知的烧结辅助，用于在高渗透型Monbtatiw中激活烧结金属（例如W和MO）的烧结，同时可以促进烧结，同时维持高温稳定性，以防止快速谷物生长，这可以通过高渗透晶元边界的假设效应来解释。这些RHEN具有纳米合金和超铁粒金属的最高温度稳定性。
Nanocrystalline alloys (nanoalloys) are prone to grain growth. It is known that grain boundary segregation and precipitation can stabilize nanoalloys, but the stabilization becomes less effective at high temperatures and adding grain growth inhibitors often reduces sinterability. Herein, we have simultaneously achieved improved sinterability and exceptional high-temperature stability for a class of MoNbTaTiW-based refractory high-entropy nanoalloys (RHENs). Bulk pellets of RHENs were fabricated through planetary ball milling and spark plasma sintering, achieving 93-96% relative densities with 50-100 nm grain sizes for three compositions. For example, Mo17.8Nb17.8Ta17.8Ti17.8W17.8Ni6Zr5 sintered at 1300 °C attained ~96% relative density with ~55 nm mean grain size. Moreover, these RHENs exhibited exceptional stability at 1300 °C. Both Ti17.8Nb17.8Mo17.8Ta17.8W17.8Ni6Zr5 and Mo18.8Nb18.8Ta18.8Ti18.8W18.8Ni6 retained <150 nm grain sizes with >96% of the theoretical densities after five hours annealing at 1300 °C. Notably, the addition of Ni, a well-known sintering aid for activated sintering of refractory metals such as W and Mo, in high-entropy MoNbTaTiW can promote sintering while maintaining high-temperature stability against rapid grain growth, which can be explained by hypothesized effects of high-entropy grain boundaries. These RHENs possess some of the highest temperature stability achieved for nanoalloys and ultrafine-grained metals.
