摘要
随着核电装备等领域对零件材料性能的要求日益严格,成分随结构位置变化的功能梯度材料(Functionallygraded material,FGM)应用愈加广泛。基于激光增材制造技术可以实时调控沉积材料成分的优势,采用同轴送粉定向能量沉积(Directed energy deposition,DED)制备不同成分变化率的316L不锈钢和Inconel 718 (IN718)高温合金功能梯度材料,包括成分变化率10%,成分变化率20%和成分突变三种试样。采用金相分析、显微组织分析、能谱分析、显微硬度和拉伸试验对各功能梯度材料的组织和力学性能进行表征。结果表明:自下而上随着IN718含量的增加,Ni元素和Nb元素含量增加,显微硬度近线性提高;铁/镍含量的线性拟合表明,无论是渐变功能梯度材料还是突变功能梯度材料,显微硬度与IN718高温合金的含量呈正相关;突变功能梯度材料在界面处存在过渡区,使元素在层间充分扩散;材料性能差异大、成分变化过快和Laves相的存在是导致界面结合性能差,产生裂纹的重要因素;梯度成分为10%的功能梯度材料拉伸性能最好,平均极限拉伸强度最高为526 MPa。研究结果将有助于选择合适的梯度变化方式,了解激光增材制造功能梯度材料的成形机理。
With the increasing requirements for stringent material performance in nuclear power equipment and other fields, preparing functionally graded material(FGM) with variable elemental composition has become a developing trend. Taking the advantage of laser additive manufacturing in controlling multiple sedimentary components, different composition gradients(10%, 20% and abrupt)with 316L stainless steel and Inconel 718(IN718) are prepared by coaxial powder feeding directed energy deposition(DED). The microstructures and mechanical properties of different FGMs are analyzed by metallographic analysis, microstructure analysis, energy spectrum analysis, microhardness and tensile test. The results show that both the contents of Ni/Nb elements and microhardness increased with the increase of IN718. For gradient or abrupt FGM, microhardness is positively correlated with the content of IN718based on the linear fitting of Fe and Ni elements contents. The transition zone located in the interface of abrupt FGM makes the elements diffuse sufficiently between layers. Three important factors, i.e., the large differences in materials properties, the rapid change of composition and the existence of Laves phase lead to poor interface bonding performance and cracks. The best tensile properties with the highest average ultimate tensile strength(526 MPa) are obtained by the FGM with composition gradient of 10%.The findings will be helpful to choose appropriate gradient variation and understand the forming mechanism of functionally graded materials fabricated by laser additive manufacturing.
作者
李鹏飞
李亮亮
周建忠
巩亚东
冯爱新
鲁金忠
LI Pengfei;LI Liangliang;ZHOU Jianzhong;GONG Yadong;FENG Aixin;LU Jinzhong(School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013;Engineering Technology Center,Shenyang Aircraft Corporation,Shenyang 110000;School of Mechanical Engineering and Automation,Northeastern University,Shenyang 110819;College of Mechanical&Electrical Engineering,Wenzhou University,Wenzhou 325035)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2022年第17期226-239,共14页
Journal of Mechanical Engineering
基金
国家重点研发计划(2019YFB2005401)
航空动力装备振动及控制教育部重点实验室开放基金(VCAEM202208)
国家自然科学基金(51775250,51875265)
江苏省自然科学基金(BK20210758)
江苏省先进制造技术重点实验室开放课题(HGAMTL-2103)资助项目。
关键词
功能梯度材料
定向能量沉积
微观组织
成分梯度
力学性能
functionally graded material
directed energy deposition
microstructure
composition gradient
mechanical properties
