Structure refinement, mechanical properties and feasibility of deformation of hypereutectic Al-Fe-Zr and Al-Ni-Zr alloys subjected to ultrasonic melt processing
Structure refinement, mechanical properties and feasibility of deformation of hypereutectic Al-Fe-Zr and Al-Ni-Zr alloys subjected to ultrasonic melt processing
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DOI：
10.1016/j.msea.2020.139567
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发表时间：
2020-06-24
期刊：
影响因子：
6.4
通讯作者：
Limmaneevichitr, Chaowalit
中科院分区：
文献类型：
--
作者：
Chankitmunkong, Suwaree;Eskin, Dmitry G.;Limmaneevichitr, Chaowalit
过共晶Al-Fe和Al-Ni合金提供了潜在的有吸引力的性能组合，例如高温强度和稳定性、高弹性模量和低热膨胀系数。然而，除非这些合金的结构得到细化，使得它们的加工成为可能，否则这种潜力无法达到。在这项研究中，我们首次应用超声熔体处理细化过共晶Al-4% Fe和Al-8% Ni合金与0.3重量% Zr添加剂的组织。初生Al 3Fe和Al 3 Ni颗粒以及铝/共晶晶粒都显著细化。结果表明，空泡诱导的初生Al 3 Zr晶体的破碎在金属间化合物以及铝的形核中起着重要的作用。此外，由于组织细化，超声处理后合金的硬度和拉伸性能显著提高，这也有助于显著提高合金的延展性。结果表明，断裂模式由脆性断裂向韧性断裂转变。延展性的增加使得合金适合于热变形，这通过实验室规模的热轧来证明。此外，合金的沉淀硬化可以通过在450摄氏度下的高温退火来实现，这是由于在凝固时在Al固溶体中保留Zr。的Zr在Al中的过饱和固溶体的组合物的分析和扫描和透射电子显微镜，证实了连贯的Al 3 Zr纳米粒子的沉淀的结果是支持的。结果表明，超声熔炼与Zr合金化相结合，可开发出基于Al-Fe系和Al-Ni系的新型超奥氏体铸造和变形合金。
Hypereutectic Al-Fe and Al-Ni alloys offer a potentially attractive combination of properties, e.g. hightemperature strength and stability, high elastic modulus and low coefficient of thermal expansion. This potential, however, cannot be reached unless the structure of these alloys is refined so that their processing becomes possible. In this study, we for the first time apply ultrasonic melt processing for refining the structure of hypereutectic Al-4% Fe and Al-8% Ni alloys with 0.3 wt% Zr addition. Both primary Al3Fe and Al3Ni particles as well as aluminum/eutectic grains are significantly refined. It is suggested that cavitation-induced fragmentation of primary Al3Zr crystals plays a significant role in the nucleation of intermetallics as well as aluminum. Furthermore, the hardness and tensile properties of the alloys substantially increase after ultrasonic treatment due to the refined structure, which also contributes to the considerably enhanced ductility of the alloys. As a result, the fracture mode changes from brittle fracture to ductile fracture. The increase in ductility makes the alloys suitable for hot deformation, which is demonstrated by lab-scale hot rolling. In addition, precipitation hardening of the alloys can be achieved by high-temperature annealing at 450 degrees C due to retained Zr in the Al solid solution upon solidification. The results are supported by the analysis of the composition of a supersaturated solid solution of Zr in Al and scanning and transmission electron microscopy that confirms the precipitation of coherent Al3Zr nanoparticles. It is demonstrated that a combination of ultrasonic melt processing and alloying with Zr makes it feasible to develop new class of hypereutectic casting and wrought alloys based on the Al-Fe and Al-Ni systems.