高强铝合金电磁-深回热均匀凝固行为

The heterogeneous distributions of composition and solidification structure are the critical problems in producing ingots of high strength aluminum alloys. The present project uses the electromagnet-deep backheatingtechnology, the temperature fieldis studied under the various electromagnet-deep backheating processes, the controlling method of temperature field is obtained.The uniformities of solidification structure and macro/micro-segregationsare studied under various electromagnet-deep backheating processes, the coupled mathematic model including the phase diagram calculation, multi-physical fields, multi-components, multi-scale and multi-phases is built, which reveals the controlling rules and mechanism of the uniformities of composition and solidification microstructure, solves the difficulty in producing the large-size ingots of high strength aluminum alloys and provide guidance for the excellent ingots needed urgently by the large aircraft project; the electromagnet-deep backheating combined with short time and high temperature technology is developed for achieving the homogenization, which provides a new process with low energy consumption and short process for producing the ingots of aluminum alloys and promotes powerfully the development of aluminum industry in China.

为了解决高强铝合金大尺寸铸锭制备过程成分和组织多尺度不均匀这一重要问题，本项目通过使用电磁-深回热技术，研究不同电磁-深回热工艺下的温度场，获得电磁-深回热工艺下温度场的工艺调控方法；研究不同电磁-深回热工艺下凝固组织均匀性和宏/微观偏析，建立一个耦合相图计算、多物理场、多组元、多尺度和多相耦合数学模型，揭示成分与组织宏/微观均匀性调控规律和机制，突破高强铝合金大尺寸铸锭制备技术的瓶颈，为制备出大飞机工程急需的优质铸锭提供指导；发展电磁-深回热工艺配合短时高温均匀化实现铸锭均匀化方法为铝合金产品生产提供一种低耗能短流程全新的新工艺，有力的推动我国铝加工的发展。

本项目通过使用电磁-深回热技术解决了铝合金铸锭制备过程成分和组织多尺度不均匀这一重要问题。通过本项目的实施，获得：电磁场能够显著细化铸锭的微观组织和均匀其分布，并能够消除气刀引起的微观组织粗化和不均匀分布；铸锭微观偏析的减小主控机制为深回热现象引起凝固过程合金元素的反扩散；铸锭宏观偏析的减小是电磁场和深回热现象共同作用的结果。本项目成果的应用突破高强铝合金大尺寸铸锭制备技术的瓶颈， 为制备出大飞机工程急需的优质铸锭提供指导；发展电磁-深回热工艺配合短时高温均匀化实现铸锭均匀化方法为铝合金产品生产提供一种低耗能短流程全新的新工艺，有力的推动我国铝加工的发展。