双相阻尼镁合金的成型工艺、微观组态及性能影响研究

This project is aimed at the needs of lightweight and noise reduction in the aerospace and civil transportation fields. It is planned to select a dual-phase damping magnesium alloy containing LPSO phase as the research object. By numerically simulating the macro-physics fields such as velocity field, strain field and temperature field in the squeeze casting process, combined with experimental analysis, the solidification law of the alloy in the liquid forming process is studied, and the precise control of the solidification structure of the magnesium alloy is achieved. Based on the design criteria of the damping magnesium alloy, combined with the heat treatment process, the solid-solution atomic content, grain size, and the size and morphology of the second phase in the magnesium alloy are comprehensively controlled, and the influence mechanism of squeeze casting and heat treatment on the microscopic configuration is discussed. The influence of process parameters on mechanical and damping properties. In-depth exploration of the damping mechanism of dual-phase magnesium alloys, development of balance optimization theory of damping and mechanics of magnesium alloys, establishment of liquid molding process, microstructure and strength, damping balance control model, to provide theoretical guidance for the development of new high strength and high damping magnesium alloys.

本项目针对于航空航天及民用交通领域轻量化、减振降噪的需求，拟选取含有LPSO相的双相阻尼镁合金为研究对象。通过数值模拟挤压铸造过程中速度场、应变场和温度场等宏观物理场，结合实验分析，研究液态成型过程中的合金凝固规律，实现镁合金凝固组织的精确控制。基于阻尼镁合金的设计准则，结合热处理工艺，综合调控镁合金中的固溶原子含量、晶粒尺寸、第二相大小及形态等，探讨挤压铸造及热处理对微观组态的影响机制，获取工艺参数对力学及阻尼性能影响规律。深入探究双相镁合金的阻尼机制，发展镁合金阻尼与力学的平衡优化理论，建立液态成型工艺、微观组织与强度、阻尼的平衡调控模型，为研发新型高强高阻尼镁合金提供理论指导。

阻尼合金是指在一定的条件下，通过吸收能量使其具有可以减振、降噪等阻尼效应的金属材料，例如采用阻尼铜合金制备潜艇螺旋桨，可使潜艇更难以被发现。在航空航天及民用交通领域，由振动和噪声引起的问题更为突出。镁及镁合金作为阻尼性能最好的金属结构材料之一，满足当前航空航天及民用交通领域对轻量化的高强高阻尼结构材料的紧迫需求。. 本项目基于发现在镁合金中引入与基面共格的长周期堆垛有序结构（LPSO）相后，阻尼与力学性能得到同步提升的现象，选用Mg-Zn/Ni-Y体系为研究对象，制备出只含有LPSO相的双相镁合金，完成对速度场、应变场及温度场等的模拟仿真，提出工艺参数评估方法和优化策略，确定最佳工艺参数为挤压压力100MPa，型温200℃，浇注温度700℃，保压时间25s。然后探讨了热处理温度、时间对第二相形态的影响规律，获得晶界块状、杆状、晶内层片状等不同形貌的LPSO相组织。通过成份优化控制，发现Ni、Zn不同过渡元素对合金中固溶原子含量有明显影响，探讨了固溶原子等对LPSO相的演化过程的影响规律；获得不同形态LPSO具备不同强化效能，在力学方面，晶界处块状LPSO相更有利于合金的力学性能；在阻尼性能方面，杆状LPSO的析出十分有利于合金阻尼性能的提升。本研究可为阻尼镁合金在轻量化、减震降噪方面的应用提供理论指导。