基本信息
项目批准号：51601045
申请代码：E0104
项目名称：超细晶铝合金低热输入搅拌摩擦焊过程中亚稳相演化规律、再结晶机制及力学性能研究
项目负责人：
刘崇宇
依托单位：
桂林理工大学
研究期限：2017-01-01 至 2019-12-31
资助经费：21.0（万元）
项目摘要
中文摘要：
剧烈塑性变形（SPD）工艺制备的超细晶（UFG）铝合金因其优异性能而具有广阔的应用前景，然而现有SPD方法均难以制备出大尺寸UFG材料。采用搅拌摩擦焊（FSW）进行焊接有望实现UFG材料的大尺寸化，但常规FSW所引起的大幅温升会破坏其细晶结构、粗化或溶解纳米沉淀相，而极大地弱化UFG材料的性能优势。本项目拟采用低热输入FSW工艺对UFG时效强化铝合金进行焊接，通过控制焊缝区的微结构，获得高强度焊接接头；对FSW过程中亚稳相组成/尺寸/结构、晶界状态、晶粒尺寸与形态、位错密度与分布等微结构变化规律进行细致研究，以加深对UFG铝合金在热、力耦合条件下的亚稳相演化规律以及再结晶机制的理解；对制备的大尺寸UFG铝合金的力学性能数据进行分析和归纳总结，揭示低热输入FSW工艺参数对接头力学性能的影响规律。通过上述工作为SPD协同FSW制备具有工程应用价值的高性能大尺寸UFG材料提供理论依据和技术支持。
英文摘要：
Ultrafine grain (UFG) Al alloys which fabricated by severe plastic deformation (SPD) have wide application prospect for their excellent properties. However, the large bulk UFG materials have not been manufactured due to the limitations of SPD methods. Friction stir welding (FSW) may increase the size of UFG materials effectively, but the high temperature appeared in conventional FSW process leads to Al grains coarsening, nano-size metastable phase coarsening or solution, and therefore deteriorates the mechanical properties of UFG Al alloys. In this study, the low heat input FSW method will be used to weld the UFG age-hardening Al alloys, and the joints with high strength will be obtained via controlling the microstructure of weld zone during FSW process. The metastable phase evolution and recrystallization mechanism of UFG Al alloys under thermo-mechanical condition will be illuminated via the evaluation of microstructure evolution such as composition, size, and structure of metastable phase, characteristic of grain boundary, size and morphology of grain, and density and distribution of dislocation. The effects of FSW parameters on the mechanical properties of large bulk UFG Al alloys will be clarified by analysis and summary mechanical properties of the alloys. The theoretical basis and technical support for the fabrication of large bulk UFG materials using for engineering field will be clarified via this research.
——来自https://kd.nsfc.gov.cn/
