GOALI: Stability of Ni-Based Superalloy Single Crystals

该项目与佛罗里达大学和普拉特-惠特尼公司合作，在NASA-Glenn研究中心和NIST的补充投入下，开发了一个关于模型和商业镍基单晶的相平衡和机械行为的科学数据库。该组织稳定性数据库将建立在为镍基合金凝固而创建的NIST数据库的基础上。改进后的数据库将使材料工程师能够更准确地了解哪些合金容易形成有害的拓扑紧密堆积(TCP)相，以及它的形成如何影响在役部件的机械性能。已有简单的经验统计模型可以预测简单成分中的TcP相，但在复杂合金中预测精度较差。需要一个基于严格冶金原理的更精确的模型来预测合金成分和温度范围对微观组织稳定性的影响。改进后的数据库最终可用于优化现有合金以获得更稳定的成分，评估对合金偏析的敏感性，并确定最佳的热机械加工窗口。P&amp；W为研究生和PI提供支持，让他们每年延长访问P&amp；W工厂的时间，以便进行内部实验。学生将与项目顾问互动，并为电子状态报告和年度项目审查做出贡献。该项目得到了MPS多学科活动办公室和DMR金属研究计划的支持。%为了实现更高的性能、更高的效率和更低的排放，导致涡轮机进口温度更高。涡轮部件中最关键的部件是涡轮叶片，它经历高温、高应力、高周疲劳和腐蚀环境。单晶镍基高温合金是为满足涡轮部件的极端使用要求而开发的。涡轮叶片和叶片通常遇到的高温可能会导致组织和机械性能的变化。***

This GOALI program teams the University of Florida and Pratt & Whitney Corp., with additional inputs from the NASA-Glenn Research Center and NIST, to develop a scientific database for the phase equilibria and mechanical behavior of both model and commercial nickel-base single crystals. This microstructural stability database will build upon the NIST database created for solidification of Ni-base alloys. The improved database will allow material engineers to know more accurately which alloys are prone to the deleterious topological close packed (TCP) phase and how its formation affects the mechanical properties of in-service components. Simple empirical statistical models exist to predict TCP phases in simple compositions, but the models have poor predictive accuracy in complex alloys. A more accurate model based on firm metallurgical principles is needed to predict microstructural stability as a function of alloy composition and temperature ranges. The improved database can ultimately be used to optimize existing alloys to more stable compositions, assess sensitivity to alloy segregation, and define optimum thermo-mechanical processing windows. P&W provides support for the graduate students and the PI for extended visits to the P&W facility each year of the program to conduct in-house experiments. The students will interact with the program advisors and contribute to electronic status reports and annual program review. The project is supported by the MPS Office of Multidisciplinary Activities and the DMR Metals Research Program.%%%The need to achieve greater performance, higher efficiency, and reduced emissions has resulted in higher turbine inlet temperatures. A most critical component in the turbine section is the turbine blade, which experiences high temperature, high stress, high-cycle fatigue, and a corrosive environment. Single crystal Ni-base superalloys were developed to meet the extreme service requirements in the turbine section. The high temperatures typically encountered by turbine blades and vanes can result in the potential for both microstructural and mechanical property changes. ***