摘要
在T型结构增材制造过程中,交叉节点处易出现冶金结合不良及重熔缺陷等问题,制约该结构性能的提升。采用激光-电弧复合增材制造技术制备了Al-Cu合金T型结构,对交叉节点处的组织形貌进行了表征,并通过数值模拟分析了节点处熔池内的温度分布以及流动特征。结果表明,在T型结构节点处能够观察到重熔作用所导致的弧形条纹特征,该区域的模拟形貌与实际结果具有良好的一致性;熔池边界处等温线分布较为密集,内部Marangoni对流导致逆时针涡流的形成,最高流速可达0.16 m/s。依据顶层晶粒形态差异,分为顶层节点重熔区(RZI)和顶层热影响区(HAZ)。其中RZI内主要为细小的树枝晶,平均晶粒尺寸相比于HAZ降低了20.8%,内部析出相主要为与α-Al基体呈非共格界面的大尺寸θ(Al_(2)Cu)相;平均显微硬度可达(98.4±6.4)HV_(0.1),相比于未重熔区最高提升约14.0%。
During the additive manufacturing process of T-shaped structure,it is prone to the problems such as poor metallurgical bonding and remelting defects at the intersections,which restrict the improvement of the performance.In this paper,T-shaped structure of Al–Cu alloy was fabricated by the laser–arc hybrid additive manufacturing.The microstructure at the intersections were characterized,and the temperature field and flow characteristics in the molten pool were analyzed by numerical simulation.The results show that the curved stripes caused by remelting can be observed at the intersections of the structure,and the simulated morphology of this region showed great agreement with the actual.The isotherm distribution was denser at the edge of the molten pool.The internal Marangoni convection led to the formation of counterclockwise vortices with a maximum velocity of 0.16 m/s.According to the differences of the grain morphology,it can be divided into the remelting zone of intersection(RZI)and the heat-affected zone(HAZ).RZI was mainly composed of fine dendrites,and the average grain size was 20.8%lower than that in HAZ.The precipitates were mainly the large-sizeθ(Al_(2)Cu)phases which were incoherent with theα-Al matrix.The average microhardness can reach(98.4±6.4)HV_(0.1),which was up to 14.0%higher than that in the unremelting zone.
作者
王儒政
马广义
吴胜男
刘德华
牛方勇
吴东江
WANG Ruzheng;MA Guangyi;WU Shengnan;LIU Dehua;NIU Fangyong;WU Dongjiang(AECC Aero-Engine Control System Institute,Wuxi 214063,China;State Key Laboratory for High-Performance Precision Manufacturing,Dalian University of Technology,Dalian 116024,China)
出处
《航空制造技术》
CSCD
北大核心
2024年第9期62-69,77,共9页
Aeronautical Manufacturing Technology
基金
国家自然科学基金(52175291)
中国高校基本科研业务费(DUT21YG116)。
关键词
激光-电弧复合增材制造
AL-CU合金
T型结构
组织形貌
熔池流动
Laser-arc hybrid additive manufacturing
Al–Cu alloy
T-shaped structure
Microstructure morphology
Molten pool flow
