Investigations of Process Optimization, Microstructure Modification and Material Performance Improvement in High Deposition-rate Laser Metal Deposition of Inconel 718

Inconel 718 高沉积速率激光金属沉积工艺优化、微观结构改性和材料性能改进的研究

基本信息

批准号：
317809677
负责人：
Dr.-Ing. Andres Gasser
金额：
--
依托单位：
Fraunhofer-Institut für Lasertechnik (ILT)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/317809677?language=en
关键词：
Investigations Process Optimization Microstructure Modification

项目摘要

It is one of the most important developing trends of the modern manufacturing industry to realize the integrated designand fabrication of large-scale metal components with short delivery time, which is exactly one of the key developmentdirections of Laser Metal Deposition (LMD). This project focuses on the High Deposition-Rate LMD (HDR-LMD) ofInconel 718 (IN718) which is a typical precipitation strengthened nickel based super-alloy and widely used in the inaircraft engine industries. Compared with conventional LMD (deposition rate ~0.5kg/h), the aim in HDR-LMD is thedeposition of several kilograms per hour. On one hand, material defects, such as porosity and cracking which aredetrimental for material performance, occur more often. The laser intensity distribution and the powder streamdistribution as well as the powder characteristics and gas environment have strong effects on material defects. On theother hand, the as-deposited material has a lower strength and a higher ductility, which is believed to be a result of thelower scale and degree of Nb segregation. Thus, it should be possible to achieve superior material performance bytaking advantage of the microstructure characteristics. Therefore, we propose the following work. Initially, in order touse the laser energy efficiently and suitably, the matching between laser intensity distribution and powder stream willbe established, based on which a HDR-LMD nozzle will be developed/adapted. Afterwards, the effects of powdercharacteristics on material defects will be investigated, and furthermore the quality specifications for powder used forHDR-LMD will be proposed. Then, based on process monitoring (high speed camera & thermal camera) andmetallographic analysis the process will be modeled, and the material microstructures will be correlated with processparameters. Finally, the microstructure will be modified by adjusting process parameters, and moreover the adaptedheat treatment process will be developed to treat the as-deposited material to improve material performance, whichkeeps partially the high temperature Laves phases with granular morphology as a second strengthening phase. Thismay be a remarkable innovation to improve the service temperature for IN718.

实现大型金属构件、短交货期的集成设计与制造是现代制造业最重要的发展趋势之一，而这也正是激光金属沉积（LMD）的重点发展方向之一。该项目重点研究Inconel 718（IN718）的高沉积率LMD（HDR-LMD），Inconel 718是一种典型的沉淀强化镍基高温合金，广泛应用于飞机发动机行业。与传统的LMD（沉积速率~0.5kg/h）相比，HDR-LMD的目标是每小时沉积几公斤。一方面，材料缺陷，例如对材料性能有害的孔隙和裂纹，更经常发生。激光强度分布和粉末流分布以及粉末特性和气体环境对材料缺陷有很大影响。另一方面，沉积态材料具有较低的强度和较高的延展性，这被认为是Nb偏析程度较低和程度较低的结果。因此，通过利用微观结构特征应该可以实现优异的材料性能。因此，我们提出以下工作。首先，为了有效且适当地利用激光能量，将建立激光强度分布与粉末流之间的匹配，在此基础上开发/改造HDR-LMD喷嘴。随后，将研究粉末特性对材料缺陷的影响，并进一步提出用于HDR-LMD的粉末的质量规格。然后，基于过程监控（高速摄像机和热摄像机）和金相分析，将对过程进行建模，并将材料微观结构与过程参数相关联。最后，通过调整工艺参数来改变显微组织，并开发合适的热处理工艺来处理沉积态材料以改善材料性能，部分保留粒状形貌的高温Laves相作为第二强化相。这对于提高IN718的使用温度来说可能是一项了不起的创新。