基于原子团簇和共格纳米相调控实现Mg-Zn系高强镁合金高阻尼化的方法及机制探索

Aimed at the strong structure vibration associated with the higher speed and the larger power of weaponries such as air craft flying vehicles, missiles and fighters, high strength high damping magnesium alloys have become the key high-efficiency vibration absorption and light-weight structure materials avoiding the damage or the failure of electronic devices and instruments. How to resolve the contradiction between the strength and the damping capacity is a difficult bottleneck problem in the development of high strength high damping magnesium alloys. The applicants have already prepared the fine-grained Mg-Zn-Zr alloy sheets with high strength and high damping capacity, but the mechanism for high damping capacity remains unclear. The project has proposed the thought that the fine-grained Mg-Zn alloy sheets are prepared by the combination of rolling process, heat treatment and Ga alloying. The independent actions and the coupling effects of grain size, dislocation configuration and the early aging precipitates such as atomic clusters and coherent precipitates on damping capacity and mechanical properties will be systematically investigated and the related mechanisms will be clarified. The feasibility of improving damping capacity of magnesium alloys by the introduction of atomic clusters and nano-scale coherent precipitates as the damping sources and the exploit of the easy operation of non-basal slip in fine grains will be explored. Finally, the method to achieve high strength magnesium alloys with high damping capacity will be developed. The project can not only provide the scientific grounds and accumulate the experimental data for the development of high strength high damping Mg-Zn alloys, but also offer the reference values for the development of high strength high damping alloys except for the Mg-Zn system.

针对航天飞行器、导弹、战机等武器装备高速化、大功率化带来的强烈结构振动问题，高强高阻尼镁合金日益成为避免电子器件、仪器仪表振动损伤或失效的高效减振轻质结构关键材料，但如何解决镁合金强度与阻尼性能之间存在的矛盾，是研制此类材料的瓶颈。申请人前期制备出了高强高阻尼的Mg-Zn-Zr系合金细晶板材，但产生高阻尼的机制问题尚不清楚。本项目提出采用轧制变形工艺和热处理、Ga合金化配合的方法调控Mg-Zn系合金板材的微观组织，系统研究并阐明晶粒尺寸、位错组态和时效早期析出的原子团簇、共格相独立和耦合影响其阻尼性能和力学性能的规律及机制，探明将原子团簇和纳米共格相作为“阻尼源”以及利用细小晶粒容易启动非基面滑移系改善合金阻尼性能的可行性，最终探索出实现高强镁合金高阻尼化的方法。本研究可以为Mg-Zn系高强镁合金高阻尼化方法研究提供科学基础和实验依据，对其它体系高强高阻尼合金材料的研制也具有参考价值。

高强高阻尼镁合金是航天飞行器、导弹和战机等领域中电子器件、仪器仪表用高效减振轻质结构关键材料。如何解决镁合金强度与阻尼性能之间的矛盾尤为重要。本项目采用中高应变速率轧制变形工艺、热处理(固溶、固溶+短时时效、退火)、预变形和低合金化相结合调控Mg-Zn系和Mg-Ga系合金的微观组织特征包括晶粒尺寸、固溶原子、原子团簇及析出相特征(尺寸、间距)、位错组态和织构等，研究合金阻尼及力学性能与微观组织特征的相关性。通过系统的实验工作和深入的理论分析，取得了一系列重要的实验结果和结论：阐明了固溶原子特性及含量、原子团簇、共格纳米相特征因素、位错密度、孪晶密度、织构及其晶粒尺寸等因素耦合影响Mg-Zn-Zr系和Mg-Ga系合金阻尼及力学性能的规律及机制，构建了相应的关系模型，明确了将GP区和β1′共格纳米相作为新型“阻尼源”改善ZK60合金阻尼性能的可行性，证实了非基面滑移对镁合金阻尼性能的改善作用，提出了改进的G-L模型，揭示了中高应变速率轧制ZK60板材的高阻尼机制和Mg-Ga板材的高塑性机制，阐明了Mg-Ga-Zn合金力学、阻尼性能及腐蚀行为与微观组织特征的关系本质和Ga元素影响ZK60合金阻尼及力学性能的规律，探明了合金元素之间的交互作用及Ga的作用机制，明确了Mg-Zn-Zr体系合金进行Ga合金化的可行性，提出了退火处理和预轧制变形相结合制备高强高阻尼镁合金板材的新思路，发展了实现Mg-Zn系高强镁合金高阻尼化的方法。上述研究成果为高强高阻尼镁合金材料的研制提供了科学基础和积累了大量实验依据。