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Ultrahigh-strengthened intragranular κ-Al2O3 nanoparticles dispersed Mo composite prepared via SPS sintering of core-shell Mo nanocomposite powder
Journal of Materials Science & Technology ( IF 11.2 ) Pub Date : 2024-04-02 , DOI: 10.1016/j.jmst.2024.03.013
Shu-Xin Yan , Ming-Yang Li , Xiao-Bo He , Fu-Fa Wu , Shun-Hua Chen , Guo-Dong Sun

Oxide dispersion strengthening (ODS) is an effective method to improve the mechanical properties of Mo-based materials. However, the mechanical properties of traditional ODS-Mo composites are always limited by the coarsening and intergranular distribution of second-phase particles. In this work, an effective nano-reinforcement dispersion strategy was developed to fabricate an ODS-Mo composite with ultrafine grain and intragranular distribution of second-phase particles. Core-shell structural Mo nanocomposite powders, with internally distributed sub-10 nm Al2O3 dispersoids, were prepared by nano atomization doping (AD) followed by a chemical vapor transport growth strategy. Then, ODS-Mo composites with ultra-fine Mo grain (below 700 nm) and high-density intragranular κ-Al2O3 (below 20 nm) nanoparticles were prepared via spark plasma sintering (SPS), in which a coherent interface between κ-Al2O3 and Mo matrix was formed. The composites present remarkably improved hardness (above 500 HV), bend strength, and compressive yield strength (above 1664 MPa) at room temperature, with a suitable strain to fracture of 27.1 %. The calculation of strengthening mechanisms indicates that the enhancement was mainly attributed to the intragranular κ-Al2O3 nanoparticles. This nano-sized reinforcement distributed within the grain can more effectively pin dislocations and achieve dispersion strengthening in ODS-Mo composites. Therefore, this strategy can efficiently construct intragranular second-phase nanoparticles and open up new avenues to fabricate high-performance ODS-Mo composites.

中文翻译:


核壳Mo纳米复合材料粉末SPS烧结制备超高强化晶内κ-Al2O3纳米颗粒分散Mo复合材料



氧化物分散强化 (ODS) 是改善 Mo 基材料机械性能的有效方法。然而,传统 ODS-Mo 复合材料的力学性能总是受到第二相颗粒的粗化和晶间分布的限制。在这项工作中,开发了一种有效的纳米增强分散策略,以制备具有超细晶粒和第二相颗粒晶内分布的 ODS-Mo 复合材料。通过纳米原子化掺杂 (AD) 和化学蒸汽传输生长策略制备了具有内部分布的亚 10 nm Al2O3 分散体的核壳结构 Mo 纳米复合粉末。然后,通过放电等离子体烧结 (SPS) 制备了具有超细 Mo 晶粒 (700 nm 以下) 和高密度晶内 κ-Al2O3 (20 nm 以下) 纳米颗粒的 ODS-Mo 复合材料,其中 κ-Al2O3 和 Mo 基体之间形成了相干界面。复合材料在室温下表现出显著提高的硬度(高于 500 HV)、弯曲强度和压缩屈服强度(高于 1664 MPa),适宜断裂应变为 27.1 %。强化机制的计算表明,强化主要归因于晶内 κ-Al2O3 纳米颗粒。这种分布在晶粒内的纳米级增强材料可以更有效地固定位错并在 ODS-Mo 复合材料中实现色散强化。因此,该策略可以有效地构建晶内第二相纳米颗粒,并为制造高性能 ODS-Mo 复合材料开辟新途径。
更新日期:2024-04-02
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