Ma Binghua, Gómez-Recio Isabel, Mazerolles Léo, Mazeran Pierre-Emmanuel, Sanchez Clément, Delalande Stéphane, Portehault David
Sorbonne Université, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4 place Jussieu, Paris, F-75005, France.
Stellantis, Centre Technique de Vélizy, route de Gisy, Vélizy-Villacoublay, 78140, France.
Small. 2022 Jan;18(4):e2104091. doi: 10.1002/smll.202104091. Epub 2021 Nov 12.
Incorporating boride nanocrystals could significantly impact the mechanical properties of aluminum alloys. Molten salts synthesis offers opportunities to fabricate superhard boride nanoparticles, which can sustain the harsh conditions during the liquid-phase design of metallic nanocomposites. Here hafnium diboride-aluminum nanocomposites are unveiled from molten salt-derived HfB nanoparticles sequentially dispersed in aluminum by ultrasound treatment. The structure and size of the nanocrystals are retained in the final nanocomposites, supporting their high chemical stability. Semicoherent interfaces between the nanoparticles and the matrix are then evidenced by TEM, suggesting that the nanocrystals could promote heterogeneous nucleation of Al and then limit the Al grain size to ≈20 µm. Nanoindentation measurements reveal significant grain boundary strengthening and grain refinement effects. It is finally shown that HfB nanoparticles also enable a decrease in matrix grain size and an increase in the hardness of the AlSi Cu Mg alloy. These proof-of-concept materials are paving the way to light-weight Al matrix nanocomposites doped by molten-salt synthesized nanoparticles.
掺入硼化物纳米晶体会显著影响铝合金的力学性能。熔盐合成法为制备超硬硼化物纳米颗粒提供了机会，这些纳米颗粒能够承受金属纳米复合材料液相设计过程中的苛刻条件。在这里，通过超声处理，从熔盐衍生的HfB纳米颗粒中依次分散在铝中，从而制备出二硼化铪-铝纳米复合材料。纳米晶体的结构和尺寸在最终的纳米复合材料中得以保留，这证明了它们具有很高的化学稳定性。然后通过透射电子显微镜（TEM）证明了纳米颗粒与基体之间存在半共格界面，这表明纳米晶体可以促进Al的异质形核，进而将Al晶粒尺寸限制在约20μm。纳米压痕测量揭示了显著的晶界强化和晶粒细化效果。最终表明，HfB纳米颗粒还能使AlSi Cu Mg合金的基体晶粒尺寸减小，硬度增加。这些概念验证材料为熔盐合成纳米颗粒掺杂的轻质铝基纳米复合材料铺平了道路。
