GH4169金属粉末选区激光熔化成型工艺及性能研究

发布时间：2018-03-19 00:24

  本文选题：增材制造　切入点：选区激光熔化　出处：《兰州理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：与传统的减材或者等材制造技术原理不同,增材制造技术(Additive Manufacturinig,AM)的原理是利用微积分的思想,以添加材料的方式把三维实体自下而上分层制造,最终完成三维实体的制造过程。选区激光熔化(Selective laser melting,SLM)技术是金属材料增材制造技术的一种。国产GH4169高温合金因其具有较好的高温强度、良好的抗氧化和热腐蚀性能,而被广泛应用到航空航天等领域。但是由于采用传统铸造方法生产GH4169零部件容易出现宏观偏析及有害的Laves脆性相,锻造方法对成型件几何形状有要求,因此GH4169高温合金应用受到限制。而利用选区激光熔化成型工艺生产GH4169解决了以上传统方法中出现的问题。本文通过对国产GH4169合金粉末选区激光熔化成型工艺进行研究,利用单因素变量方法对成型过程的参数(扫描间距、扫描速度、激光功率)进行研究,以SLM成型件致密度、表面质量及孔洞为衡量指标,最终得到最佳的成型参数:铺粉层厚40um,激光光斑大小为100um,基板预热80℃,扫描间距为70um,扫描速度为1750~2250mm/s,激光功率为300W~375W。对成型件组织及性能进行分析。分析结果表明:选区激光熔化成型件组织主要由尺寸小于0.3um的柱状晶和胞状晶组成。柱状晶粒贯穿多个熔道呈外延生长,且形成大角度晶界;成型件不同的方位硬度不一致,成型件的拉伸性能优于铸件标准。热处理可以大幅度提高SLM成型件的硬度及拉伸性能,均达到锻件标准,成型件热处理前后的拉伸断裂模式均为韧性断裂。
[Abstract]:In contrast to the traditional manufacturing principles of subtractive or isotropic materials, the principle of incremental manufacturing technology is to use the idea of calculus to delaminate three-dimensional entities from bottom to top by adding materials. The selective laser melting laser melting (SLM) technology is a kind of metal material augmentation technology. The domestic GH4169 superalloy has good high temperature strength, good oxidation resistance and hot corrosion resistance. It is widely used in aerospace and other fields. However, because the traditional casting method is easy to produce GH4169 parts with macro segregation and harmful Laves brittle phase, the forging method requires the geometric shape of the molded parts. Therefore, the application of GH4169 superalloy is restricted, and the problems in the traditional methods mentioned above are solved by using the selective laser melting molding process. This paper studies the selective laser melting molding process of domestic GH4169 alloy powder. Single factor variable method was used to study the parameters (scanning distance, scanning speed, laser power) of the molding process. The density, surface quality and porosity of the SLM molded parts were taken as the measurement index. Finally, the best molding parameters are obtained: the thickness of powder layer is 40 ums. the laser spot is 100 um. the substrate is preheated at 80 鈩，

本文编号：1632019