Improvement in Geometrical Accuracy and Mechanical Property for Arc-Based Additive Manufacturing Using Metamorphic Rolling Mechanism
Improvement in Geometrical Accuracy and Mechanical Property for Arc-Based Additive Manufacturing Using Metamorphic Rolling Mechanism
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DOI：
10.1115/1.4032079
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发表时间：
2016-11
影响因子：
4
通讯作者：
Yang Xie;Haiou Zhang;Fei Zhou
中科院分区：
文献类型：
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作者：
Yang Xie;Haiou Zhang;Fei Zhou
背景：增材制造（AM），或称3D打印，由于其材料利用率高、产品设计灵活性强以及固有的无模工艺等特点，正引起当代人们的极大兴趣。电弧增材制造是一种极具发展前景的增材制造方法，具有高沉积速率和良好的堆积质量。由AAM制成的部件是通过金属丝沉积的叠加焊珠制成的。与基于激光的增材制造（LAM）不同，AAM更难控制。由于能量源的能量输入大，以及熔融金属材料的流动性，会出现缩松、开裂、残余应力、变形等瓶颈问题。因此，较差的几何精度和机械性能使AAM无法实现工业应用。特别是在航空航天工业中，结构和机械性能规范是严格和关键的。方法：本文提出了一种利用热轧工艺辅助电弧焊的新型混合制造方法，解决了上述问题。首先，利用变质机理理论建立了微型变质滚动机构。MRM的结构和拓扑结构可以根据部件的特征进行改变，以滚动头的顶面和侧面。随后，分别搭建了三道单层多层墙体进行对比。结果：顶面轧制时，累计最大高度绝对误差由2.4 mm减小到0.2 mm。对于侧面轧制，最大宽度绝对误差由0.45 mm减小到0.12 mm。每层厚度为1.55 mm，在混合制造方法下精确控制。与AAM试样相比，屈服强度提高4.0%，极限抗拉强度提高6.6%，延伸率提高7.4%。改进后的力学性能优于变形材料。纵向上，屈服强度提高9.3%，极限抗拉强度提高1.8%，延伸率提高10.4%。结论：轧制结果显示，在几何精度的建造特征显著改善。拉伸试验结果表明其力学性能有所改善。轧制试样的力学性能在行程方向上优于变形试样。显微组织比较表明，在垂直方向上观察到柱状晶粒，熔合区受到抑制。最终，大型航空部件的制造验证了混合制造技术在工业应用中的可行性。关键词：电弧增材制造，热轧，变质机理
Background: Additive manufacturing (AM), or 3D printing, is drawing considerable contemporary interest due to characteristic of high material utilization, great flexibility in product design and inherent mouldless process. Arc-based additive manufacturing (AAM) is a promising AM method with high deposition rate and favorable build-up quality. Components made by AAM are fabricated through superimposed weld beads deposited from metal wire. Unlike laser-based additive manufacturing (LAM), AAM is more difficult to control. Because of the large energy input of the energy source and the liquidity of the melting metal material, bottleneck problems like shrinkage porosity, cracking, residual stresses and deformation occur. Resultant poor geometrical accuracy and mechanical property keep AAM from industrial application. Especially in the aerospace industry, structural and mechanical property specifications are stringent and critical. Method of approach: This paper presents a novel hybrid manufacturing method by using hot-rolling process to assist the arc welding to solve above problems. Initially, a miniature metamorphic rolling mechanism (MRM) was developed using metamorphic mechanism theory. Configuration and topology of the MRM can change according to the feature of the components to roll the top and lateral surfaces of the bead. Subsequently, three single-pass multi-layer walls were built respectively for comparison. Results: For top surface rolling, accumulated maximum height absolute error was reduced from 2.4 mm to 0.2 mm. For lateral surface rolling, maximum width absolute error was reduced from 0.45 mm to 0.12 mm. The thickness of each layer is 1.55 mm, controlled accurately under hybrid manufacturing method. The mechanical properties were improved by 4.0% for yield strength, 6.6% for ultimate tensile strength and 7.4% for elongation in travel direction compared with AAM specimens. The improved mechanical properties were superior to wrought material. In vertical direction, the improvement is 9.3% for yield strength, 1.8% for ultimate tensile strength and 10.4% for elongation. Conclusions: The rolled results show significant improvement in geometrical accuracy of the built features. Tensile test results demonstrate improvement in mechanical properties. The improved mechanical properties of rolled specimens are superior to wrought material in travel direction. Microstructure comparisons indicate columnar grains observed in vertical direction and fusion zones were suppressed. Eventually, fabrication of a large-scale aerospace component validates the feasibility of industry application for the hybrid manufacturing technology. Keywords: Arc-based additive manufacturing, hot rolling, metamorphic mechanism