孕育剂SiC对Al-Zn-Mg-Cu合金GMAW电弧增材制造构件微观组织及力学性能的影响  

Effect of inoculant SiC on the microstructure and mechanical properties of Al-Zn-Mg-Cu alloy GMAW arc additive manufactured components

作　　者：李洋[1] 袁涛[1] 张元彬[2] 蒋晓青[1] 李博阳 LI Yang;YUAN Tao;ZHANG Yuanbin

机构地区：[1]北京工业大学材料与制造学部,北京100124 [2]山东建筑大学材料科学与工程学院,山东济南250101

出　　处：《焊接技术》2022年第4期6-12,I0001,共8页Welding Technology

摘　　要：Al-Zn-Mg-Cu合金以其高比强度、优良的导热性与耐腐蚀性常用于航空航天、汽车等领域,采用电弧增材制造并探索添加孕育剂的作用对于改善高强铝合金性能、促进其工程应用具有重要意义。本研究采用Al-Zn-Mg-Cu合金焊丝进行GMAW电弧增材制造,通过添加SiC颗粒改善构件微观组织及力学性能,并对比了微米级与纳米级SiC颗粒作用效果。结果表明,常规Al-Zn-Mg-Cu合金电弧增材沉积件微观组织有明显分层现象,随着沉积层数增加,热量累积,晶粒变得粗大且向着柱状晶的形态转化。而SiC的加入抑制了微观组织向柱状晶转变的趋势,使沉积件整体微观组织分布更加均匀,同时晶粒平均尺寸整体由94.57μm可细化至59.3μm,细化程度为37.29%,局部最高可细化44.26%。在力学性能上提高了Al-Zn-Mg-Cu合金电弧增材沉积件的硬度,由HV112提升至HV120,提升程度约7.14%,且硬度波动变化减小。另外,SiC颗粒的添加提高了Al-Zn-Mg-Cu合金电弧增材沉积件的强度与韧性。整体上看,与添加微米级SiC颗粒相比,添加纳米级SiC颗粒Al-Zn-Mg-Cu合金电弧增材制造得到的构件微观组织更加均匀细小,力学性能更加优越。Al-Zn-Mg-Cu alloy is commonly used in aerospace,automotive and other fields for its high specific strength,excellent thermal conductivity and corrosion resistance. It is important to use arc additive manufacturing and explore the role of adding inoculants to improve the performance of high-strength aluminum alloys and promote their engineering applications. In this study,Al-Zn-Mg-Cu alloy wire was used for GMAW arc additive manufacturing. The microstructure and mechanical properties of the components were improved by adding Si C particles,and the effects of micron-scale and nano-scale Si C particles were compared. The result showed that the microstructure of the conventional Al-Zn-Mg-Cu alloy arc deposited parts had obvious delamination phenomenon,and with the increase of deposited layers and heat accumulation,the grains became coarse and transform towards the morphology of columnar crystal.However,the addition of Si C suppresses the tendency of microstructure transformation to columnar crystals,and made the overall microstructure of the deposited parts more uniformly distributed. Meanwhile,the overall average grain size could be refined from 94. 57 μm to 59. 3 μm,with a degree of refinement of 37. 29% and a maximum local refinement of44. 26%. The hardness of the Al-Zn-Mg-Cu alloy arc additive deposited parts was improved in mechanical properties,and the variation of hardness fluctuation was reduced. In addition,the addition of Si C particles improved the strength and toughness of the Al-Zn-Mg-Cu alloy arc additive deposited parts. Overall,the microstructure of the components obtained by adding nanoscale Si C particles to Al-Zn-Mg-Cu alloys by arc additive manufacturing was more uniform and fine,and the mechanical properties were superior compared to those obtained by adding micron-scale Si C particles.

关 键 词：AL-ZN-MG-CU合金 增材制造 孕育剂 晶粒细化 SIC 

分 类 号：TG444[金属学及工艺—焊接] TG457.1