摘要
针对目前激光选区熔化难以直接成形大尺寸、高强度铝合金构件的问题,对定向能量沉积(DED)连接激光选区熔化成形Al-Mg-Sc-Zr合金的工艺进行研究,分析缺陷分布的位置、形貌以及对力学性能的影响,对比分析定向能量沉积参数以及超声外场辅助下连接试样的微观组织、元素分布和力学性能,并通过热等静压进一步提升力学性能。结果表明:缺陷主要分布在基材与连接区交界的熔合区,密集气孔聚集导致熔合区硬度远低于连接区和基材的硬度,并使整体拉伸性能弱化。在75~150 J/mm^(2)激光能量密度范围内,随能量密度增大,致密度和抗拉强度均提升。采用3000 W激光功率、5 mm/s扫描速率、3.7 g/min送粉速率,得到最高的熔合区硬度、连接区致密度以及抗拉强度,分别为90 HV、90.83%、203.38 MPa。超声外场辅助会促进Al3(Sc,Zr)强化相的析出并细化晶粒,且能够有效减少气孔的数量和缩小气孔的尺寸。超声后试样的综合力学性能得到显著提升,熔合区硬度为95 HV,致密度为93.06%,抗拉强度为292 MPa,较未加超声时分别提高了5%、2.4%和44%。超声后采用热等静压的后处理方法,可使综合力学性能得到进一步提升,熔合区硬度为160 HV,致密度为99.99%,抗拉强度为405.71 MPa,较未热等静压时分别提高了68.4%、7.4%和38.9%。
Objective As structural materials,aluminum alloys are widely employed in aerospace,especially in the 5 series and 7 series aluminum alloys.Currently,most of these aluminum alloy materials are prepared by traditional forging processes.Additive manufacturing technology,especially selective laser melting(SLM)forming technology,has gradually demonstrated enormous technological advantages under numerous demanding requirements such as weight reduction and functional upgrading of aerospace structures.However,currently,SLM forming of aluminum alloy structural components mainly relies on low-strength aluminum alloys,and these aluminum alloys'strength and other indicators cannot meet the performance requirements of 5 series and 7 series aluminum alloys.Additionally,the size of structural aluminum alloy components formed by SLM often has certain limitations.The development of high-strength Al-Mg-Sc-Zr forming and joining processes is significant for the large-scale and integrated development of aerospace equipment.Currently,there is relatively little research on the joining technology of SLM-formed Al-Mg-Sc-Zr alloys both domestically and internationally.Therefore,we hope to find a method to improve the joining performance of high-strength aluminum alloys.Methods Due to the difficulty in forming large-scale high-strength aluminum components by SLM directly,we investigate the directed energy deposition(DED)joining process of Al-Mg-Sc-Zr fabricated by SLM.The distribution and morphology of defects and their influence on the mechanical properties are analyzed.Moreover,the microstructure,element distribution,and properties of specimens joining with different DED process parameters and the addition of ultrasonic external field assistance are compared,and mechanical properties are improved by hot isostatic pressing.Results and Discussions The results indicate that the defects are mainly distributed in the fusion zone,which is the interface between the base and the joining zone(Fig.4).The aggregation of dense pores at the fusion z
作者
尚晓峰
董建舟
张英伟
王志国
赵宇辉
何振丰
赵吉宾
Shang Xiaofeng;Dong Jianzhou;Zhang Yingwei;Wang Zhiguo;Zhao Yuhui;He Zhenfeng;Zhao Jibin(School of Mechatronics Engineering,Shenyang Aerospace University,Shenyang 110135,Liaoning,China;Shenyang Institute of Automation,Chinese Academy of Sciences,Shenyang 110016,Liaoning,China;Institutes for Robotics and Intelligent Manufacturing,Chinese Academy of Sciences,Shenyang 110169,Liaoning,China;AVIC Shenyang Aircraft Industrial(Group)Co.,Ltd.,Shenyang 110850,Liaoning,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2024年第4期261-272,共12页
Acta Optica Sinica
基金
沈阳市中青年科技创新人才支持计划项目(RC220527)
“兴辽英才计划”青年拔尖人才(XLYC2203154)
揭榜挂帅项目(2022JH1/10800048)
2023年数字辽宁智造强省(智造强省方向)专项(辽工信投资[2023]171号)
国防科技重点实验室基金(61420052022KJW05)。
关键词
光学设计
定向能量沉积
连接
AL-MG-SC-ZR合金
超声外场辅助
力学性能
热等静压
optical design
directed energy deposition
joining
Al-Mg-Sc-Zr alloys
ultrasonic external field assistance
mechanical properties
hot isostatic pressing
