The Role of Carbon in Solidification of Nickel-Base Single Crystals

碳在镍基单晶凝固中的作用

• 批准号: 9807648
• 负责人: Tresa Pollock
• 金额: $ 29.63万
• 依托单位: Carnegie-Mellon University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 2000-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9807648&HistoricalAwards=false
• 关键词: Role; Carbon; Solidification; Nickel; Base

9807648 Pollock Carbon additions have a beneficial effect on reducing the incidence of grain defects that develop during solidification of superalloy single crystals. This research examines the fundamental basis for this effect. The program is a collaboration between Carnegie Mellon University and General Electric Corporate Research and Development and General Electric Power Systems, and falls under the GOALI program funded by the DMR Metals Research Program and the MPS Office of Multidisciplinary Activities. The specific goals of this research on superalloys are twofold: (1) to determine the mechanisms by which carbon additions influence grain defect formation during directional solidification, and (2) to obtain an improved understanding of the range of alloy composition over which carbon serves as a beneficial addition. This research aims to develop a better overall understanding of the processes which result in the breakdown of single crystal solidification in nickel-base alloys. This is accomplished with an experimental program that examines a number of different aspects of alloy structure and chemistry that influence the solidification process. First since refractory-rich carbides precipitate in the vicinity of the liquidus temperature, carbide structure and compositions are examined as a function of alloy chemistry. Differential thermal analysis is employed to measure solidus, liquidus, and carbide solution temperatures. To examine the distribution of alloying elements in the mushy zone and to obtain measurements of fraction solid as a function of temperature, directional solidification experiments interrupted by quenching are conducted. Electron microprobe analyses are used to characterize segregation in these samples. To examine the influence of alloy chemistry on grain defect formation, single crystal directional solidification experiments are conducted with a number of compositions that have distinctly different characteristics in terms of se gregation, carbide density, and carbide precipitation temperatures. %%% This research examines defect formation in high temperature superalloy castings and relates to applications in turbine engines. Educational benefits include student interaction with General Electric Corporation laboratories. ***

小行星9807648 碳添加剂对降低高温合金单晶凝固过程中产生的晶粒缺陷的发生率具有有益的影响。 本研究探讨了这种效应的基本依据。 该计划是卡内基梅隆大学与通用电气公司研发和通用电力系统之间的合作，福尔斯属于由DMR金属研究计划和MPS多学科活动办公室资助的GOALI计划。 这项研究的具体目标是双重的：（1）确定碳添加剂影响定向凝固过程中晶粒缺陷形成的机制，以及（2）获得对碳作为有益添加剂的合金成分范围的更好理解。 本研究的目的是发展一个更好的整体了解的过程中，导致在镍基合金单晶凝固的故障。 这是通过一个实验程序来完成的，该程序检查了影响凝固过程的合金结构和化学的许多不同方面。 首先，由于耐火材料丰富的碳化物沉淀在液相线温度附近，碳化物结构和组合物作为合金化学的函数进行检查。 差热分析用于测量固相线、液相线和碳化物溶解温度。 为了研究合金元素在糊状区的分布，并获得作为温度的函数的固体分数的测量值，进行了淬火中断的定向凝固实验。 电子探针分析用于表征这些样品中的偏析。 为了研究合金化学对晶粒缺陷形成的影响，进行了单晶定向凝固实验，其中一些组合物在偏析、碳化物密度和碳化物析出温度方面具有明显不同的特性。 本研究探讨了高温合金铸件中的缺陷形成，并与涡轮机发动机中的应用有关。 教育福利包括学生与通用电气公司实验室的互动。 ***