GOALI: Stability of Ni-Based Superalloy Single Crystals

这个GOALI项目由佛罗里达大学和普惠公司组成，在NASA格伦研究中心和NIST的额外投入下，开发了一个关于模型和商业镍基单晶相平衡和机械行为的科学数据库。该微观结构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产生有害的拓扑紧密堆积（TCP）相，以及其形成如何影响在役部件的机械性能。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。一个更准确的模型，基于坚定的冶金原理，需要预测作为合金成分和温度范围的函数的微观结构稳定性。改进后的数据库最终可用于优化现有合金，使其具有更稳定的成分，评估合金偏析的敏感性，并确定最佳的热机械加工窗口。 P W为研究生和PI提供支持，以便在计划的每一年延长对P W设施的访问，以进行内部实验。学生将与计划顾问互动，并为电子状态报告和年度计划审查做出贡献。该项目得到MPS多学科活动办公室和DMR金属研究计划的支持。实现更高性能、更高效率和减少排放的需求导致了更高的涡轮机入口温度。涡轮机部分中最关键的部件是涡轮机叶片，其经历高温、高应力、高循环疲劳和腐蚀性环境。单晶镍基高温合金是为满足涡轮机部分的极端使用要求而开发的。涡轮机叶片和轮叶通常遇到的高温可能导致微观结构和机械性能的变化。***

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. ***