双金属电子束选区熔化的硬件开发与成形实验
Dual-Material Electron Beam Selective Melting: Hardware Development and Validation Studies
电子束选区熔化(EBSM)是一种利用电子束扫描、熔化金属粉末逐层制造三维实体零件的增材制造技术。近年来,EBSM已经成功应用于多种材料的增材制造。现有EBSM工艺方面的研究主要聚焦于单种材料的成形,本研究提出一种能够利用两种粉末材料成形梯度结构的EBSM工艺,提出基于振动的粉末供给方法,并实现了两种粉末材料独立供给并混合。利用Ti6Al4V和Ti47Al2Cr2Nb两种材料进行成形。Ti6Al4V在室温下有很好的强度与塑性,而Ti47Al2Cr2Nb在高温下性能优良,但有很大的室温脆性。本研究提出的双金属EBSM工艺成功制备了Ti6Al4V/Ti47Al2Cr2Nb梯度结构,并利用光学显微镜、扫描电子显微镜、电子微探针分析等方法研究了该梯度结构的微观组织和化学成分。结果显示,梯度结构的截面厚度约为300 μm,没有裂纹,化学成分在界面处呈阶梯式变化。
Electron beam selective melting (EBSM) is an additive manufacturing technique that directly fabricates three-dimensional parts in a layerwise fashion by using an electron beam to scan and melt metal powder. In recent years, EBSM has been successfully used in the additive manufacturing of a variety of materials. Previous research focused on the EBSM process of a single material. In this study, a novel EBSM process capable of building a gradient structure with dual metal materials was developed, and a powder-supplying method based on vibration was put forward. Two different powders can be supplied individually and then mixed. Two materials were used in this study: Ti6Al4V powder and Ti47Al2Cr2Nb powder. Ti6Al4V has excellent strength and plasticity at room temperature, while Ti47Al2Cr2Nb has excellent performance at high temperature, but is very brittle. A Ti6Al4V/Ti47Al2Cr2Nb gradient material was successfully fabricated by the developed system. The microstructures and chemical compositions were characterized by optical microscopy, scanning microscopy, and electron microprobe analysis. Results showed that the interface thickness was about 300 μm. The interface was free of cracks, and the chemical compositions exhibited a staircase-like change within the interface.
增材制造 / 电子束 / 选区熔化 / 梯度材料 / 钛合金 / 钛铝合金
additive manufacturing / electron beam / selective melting / gradient materials / titanium alloy / TiAl alloy
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