摘要
采用电弧熔丝增材制造(WAAM)制备了圆柱面双层金字塔点阵结构,分析了圆柱面金字塔点阵结构的空间特征,建立了单元杆杆长数学模型,进行了圆柱面切片和路径规划,揭示了送丝速度、冷金属过渡技术(cold metal transfer, CMT)周期数和电弧枪偏移量与单元杆直径和倾角的关系。结果表明,圆柱面金字塔点阵结构具有旋转体的空间特征,其单元杆杆长随着点阵层数的增加而逐渐增加,圆柱面切片可获得增材制造路径点,通过调节送丝速度和CMT周期数可实现在2.20~5.02 mm的范围内精确控制单元杆直径,通过调节送丝速度和电弧枪偏移量可实现在30°~90°的范围内精确控制单元杆倾角。利用WAAM制备了包含300个点阵单胞的圆柱面双层金字塔点阵结构,其单元杆直径最大误差不超过2.3%,单元杆倾角最大误差不超过1.8%。
The three-dimensional lattice structureofaluminum alloy has significant advantages such as light weight,high strength,heat insulation,etc.,and it has broad application prospects in the fabrication of curved shells of ultra-high-speed aircraft.Wire and arc additive manufacturing(WAAM)has significant advantages such as high forming efficiency,high spatial freedom and controllable wire composition.WAAM is used to form three-dimensional aluminum alloy lattice structure,which can effectively avoid the problems of high aluminum alloy laser reflectivity,poor aluminum alloy powder fluidity,and large powder bed space constraints in the selective laser melting.WAAM has now become an important process method for the fabrication of metal-based three-dimensional lattice struc⁃tures,but the existing research is mainly aimed at the process method and precision control of the plane lattice structure,and there is few related research on the characteristics,slicing method and fabrication of the curved lattice structure.In this paper,the characteris⁃tics of the cylindrical pyramid lattice structure were analyzed,and the mathematical model of the unit rod length was established.The printing path was obtained by the cylindrical slicing method,and the path planning was carried out.The relationship between the wire feed speed,the number of CMT cycles,the offset of the arc gun and the diameter and inclination of the unit rod was revealed.Using ER2319 aluminum alloy welding wire as the deposition material,the WAAM system composed of Fronius TPS 4000 CMT welding pow⁃er source,KUKA KR30-HR robot and welding positioner was used to fabricate cylindrical double-layer pyramid lattice structure,and the dimensional accuracy of the fabricated lattice structure was measured using industrial microscope and image pro metallographic software.The results showed that the cylindrical pyramid lattice structure had rotating body characteristics,the mathematical model of the unit rod length established by rotation angle(θ)and rotation radius(R)showed that the unit rod length gradually increased with the increase of the number of lattice layers.Cylindrical slicing and path point extraction procedures could obtain the path points of the central axis of the unit rod of lattice structure for additive manufacturing.By adjusting the wire feeding speed and the number of CMT cycles,the diameter of the unit rod could be accurately controlled within the range of 2.20~5.02 mm,reducing the wire feeding speed and increasing the number of CMT cycles could reduce the peak temperature of molten pool without changing the diameter of the unit rod.By adjusting the wire feeding speed and the offset of the arc gun,the inclination of the unit rod could be accurately controlled within the range of 30°~90°,the offset of the arc gun at different inclination angles could deduce the corresponding cylindrical slice layer height.A cylindrical double-layer pyramid lattice structure containing 300 lattice unit cells was fabricated by WAAM.The theo⁃retical diameter of the lattice structure unit rod was 3 mm,and the theoretical inclination angle was 45°.The metallographic measure⁃ment results found that the maximum error of the unit rod diameter did not exceed 2.3%,and the maximum error of the unit rod incli⁃nation angle did not exceed 1.8%,indicating that the cylindrical lattice structure of wire and arc additive manufacturing had high ac⁃curacy.
作者
唐论
余圣甫
郑博
史玉升
陈颖
张李超
Tang Lun;Yu Shengfu;Zheng Bo;Shi Yusheng;Chen Ying;Zhang Lichao(State Key Laboratory of Materials Processing and Die&Mould Technology,School of Materials Science and Engi-neering,Huazhong University of Science and Technology,Wuhan 430074,China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2023年第4期465-474,共10页
Chinese Journal of Rare Metals
基金
国家自然科学基金重大项目(51790174)资助。
