航空材料学报2026，Vol.46Issue(9)：55-67,13.DOI:10.11868/j.issn.1005-5053.2025.000231
稀土镁合金的超声固相连接:微观组织演变特征与强化机制研究
Solid-state joining of rare-earth magnesium alloys via ultrasonic welding:microstructural evolution characteristics and strengthening mechanism
摘要
Abstract
During welding thermal cycles,magnesium alloys are highly susceptible to grain coarsening and structural changes of precipitates,leading to microstructural damage and subsequently deteriorating the performance of welded joints.Consequently,mitigating the strength degradation of magnesium alloys during welding has attracted considerable research attention in the field of magnesium alloy processing.In this study,an ultrasonic vibration-assisted solid-state joining process is employed to join a Ce-containing rare-earth magnesium alloy,and the microstructural evolution and strengthening mechanisms of the joints are systematically investigated.The results indicate that the acoustic plasticity and thermal effects induced by ultrasonic vibration promote intense dynamic recrystallization at the contact interface,resulting in significant grain refinement within the ultrasonic-affected zone,with grain sizes reduced from 250 μm in the base metal to 10-30 μm in the joint region.Simultaneously,the high-frequency mechanical shearing generated by ultrasonic vibration fragments coarse precipitates into uniformly distributed micro-and submicro-sized particles,thereby significantly enhancing precipitation strengthening.In addition,the segregation of rare-earth element Ce at the grain boundaries leads to the formation of thermally stable phases,which effectively pin grain boundaries and suppress dislocation motion,thereby mitigating microstructural degradation during the joining process.Mechanical testing demonstrates that the synergistic effects of grain-refinement strengthening,dispersion strengthening,and rare-earth strengthening enable the joint to achieve a lap-shear strength of 194.9 MPa,equivalent to 92.4%of the base metal strength.Additionally,the fracture mode transitions from interfacial brittle fracture to matrix ductile fracture.The findings provide theoretical basis and technical guidance for the development of low-damage,highly reliable joining technologies for rare-earth magnesium alloys.关键词
稀土镁合金/超声振动/第二相破碎/析出强化/晶粒细化Key words
rare-earth magnesium alloy/ultrasonic vibration/second-phase fragmentation/precipitation strengthening/grain refinement分类
航空航天引用本文复制引用
曹君,陈燕飞,朱政强,熊志林,李思嘉,杨群义..稀土镁合金的超声固相连接:微观组织演变特征与强化机制研究[J].航空材料学报,2026,46(9):55-67,13.基金项目
中国博士后科学基金(2025M770017) （2025M770017）
江西省自然科学基金(20252BAC200638) （20252BAC200638）
湖南省教育厅科学研究项目优秀青年项目(24B0986) （24B0986）
