摘要: |
针对激光选区熔化成形GH4169高温合金未熔合、孔洞和微气孔三类缺陷,在明晰其产生机理基础上,提出了粉末调控-工艺调控-热等静压调控的全流程冶金缺陷主动调控方法。结果表明,降低粉末空心粉率是控制微气孔缺陷的主要途径,建议优先选用空心粉效率更低的等离子旋转电极粉末;未熔合缺陷和孔洞缺陷主要通过工艺参数调控,提出了用于表征能量输入的熔化能量比ηm及气化能量比ηv,针对GH4169高温合金,当ηm>4.62且ηv<0.78时,可有效避免未熔合和孔洞缺陷;成形后热等静压可进一步消除内部微小缺陷,将缺陷数量降低1~2个数量级。 |
关键词: 激光选区熔化成形;GH4169;冶金缺陷;控制方法 |
基金项目:金属粉末增材制造数值模拟方法与冶金缺陷机理研究(12032002) |
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Active Control Method of Metallurgical Defects in Selective Laser Melted GH4169 |
Luo Zhiwei Yan Zhenyu Guo Bowen Zhou Qingjun Liu Han Li Donglai
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Capital Aerospace Machinery Co., Ltd., Beijing 100076
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Abstract: |
Aiming at three types of defects such as incomplete fusion, unfilled keyholes and micro-pores in laser selective melted GH4169 superalloy, on the basis of clarifying the generation mechanism, an active control method for the whole process of powder control-process control-HIP control was proposed. The results show that the micro-pores are mainly controlled by reducing the ratio of hollow powder, and it is recommended to use plasma rotating electrode powders. Incomplete fusion and unfilled keyholes are mainly controlled by adjusting process parameters. The ηm and ηv used to characterize the energy input is proposed. When ηm>4.62 and ηv<0.78, these defects in GH4169 superalloy can be effectively avoided. Hot isostatic pressing can further reduce the number of defects by 1 to 2 orders of magnitude by eliminating minor defects. |
Key words: selective laser melting;GH4169;metallurgical defects;control method |