A comparative study of Inconel 718 formed by High Deposition Rate Laser Metal Deposition with GA powder and PREP powder
A comparative study of Inconel 718 formed by High Deposition Rate Laser Metal Deposition with GA powder and PREP powder
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DOI：
10.1016/j.matdes.2016.06.037
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发表时间：
2016-10
影响因子：
8.4
通讯作者：
Chongliang Zhong;J. Chen;S. Linnenbrink;A. Gasser;S. Sui;R. Poprawe
中科院分区：
文献类型：
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作者：
Chongliang Zhong;J. Chen;S. Linnenbrink;A. Gasser;S. Sui;R. Poprawe
对气体雾化(GA)和等离子体旋转电极法(PREP)粉末高速激光沉积(HDR-LMD)Inconel718(IN718)合金的冶金性能和材料组织进行了比较研究。首先，选择了不同方法制备的相同名义粒度的粉末，并对其化学成分、孔隙率和形貌进行了表征。设计并进行了平行试验，分析了材料的冶金性能和显微组织。研究发现：与PREP粉末沉积的IN718相比，GA粉末制备的材料具有更高的孔隙率和更高的稀释区，枝晶组织更细小，Nb元素偏析程度更低，Laves相的体积分数更低。为了找出原因，定性和定量地分析了不同粉末工艺的气孔形成机理、激光能量分配、散热和凝固。结果表明：GA IN718具有较高的气孔率是由于GA粉末自身的特点，在工艺过程中引入了较多的气体，其组织优于PREP粉末，具有更细小的枝晶组织、较低的Nb偏析和较低的Laves相分数，这是由于其较高的冷却速度所致。
A comparative study on the metallurgical properties and material microstructures of Inconel 718 (IN718) deposited by High Deposition Rate Laser Metal Deposition (HDR-LMD) using Gas Atomization (GA) and Plasma-rotating Electrode Process (PREP) powders has been carried out. Initially, powders of same nominal particle size produced by different methods were selected and the chemical composition, porosity and morphology of which have been characterized. After that, parallel experiments have been designed and performed, and the metallurgical properties and material microstructures have been analyzed. It is found: compared to IN718 deposited with PREP powder, material formed by GA powder has higher porosity and higher dilution zone whereas finer dendrite structure, lower Nb element segregation and lower volume fraction of Laves phase. In order to figure out the reasons, the mechanisms of pores formation, the laser energy allocation, heat dissipation and solidification of the processes using different powders have been qualitative and quantitative analyzed. It concludes: the high porosity of GA IN718 is due to that more gas has been drawn into the process because of the characteristics of GA powder; the microstructures of GA IN718 is superior to that of PREP powder, showing finer dendrite structure, lower Nb segregation and lower Laves phase fraction, which is due to its higher cooling rate.