Recoating and Refurbishment of Single crystal Ni- Based Superalloys for Advanced Gas Turbines

先进燃气轮机用单晶镍基高温合金的重涂和翻新

• 批准号: 10650078
• 负责人: OKAZAKI Masakazu
• 金额: $ 2.24万
• 依托单位: The University of Tokyo (1999)Nagaoka University of Technology (1998)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650078/
• 关键词: Recycle and Recoating; Cellular Transformation; Single Crystal Ni-base Superalloy; Kinetics; Nondestructive detection; Fatigue strength; Damage; Reheating for damage recovery; 産業用ガスタービン; 単結晶Ni基超合金; リサイクル; リコーティング; ポリゴン化; 高温疲労強度; 抑制処理

This work has been conducted to make clear the formation of the abnormal microstructure, or cellular transformation, resulting from the local plastic deformation in single crystal Ni-base superalloys, CMSX-2 and CMSX-4, in order to get fundamental understanding to establish the refurbishment technology for advanced gas turbine components. During the study special attention was paid to get understandings on the nucleation and growth behavior from viewpoints of crystallography and thermo dynamics. The relationship between the transformation and the actual failure damages was also explored. Furthermore, the effect of the local cellular transformation on high temperature fatigue strength was investigated.The conclusions obtained are summarized as follows :(1) When CMSX-2 and CMSX-4 were subjected to damages associated with local plastic deformation, followed by the re-heat treatments, the cellular transformation associated with γ/γ' microstructure coarsened in lamellar or equiaxed array wa … More s originated. This was not a special phenomenon, but it was actually reproduced in the material subjected to fatigue and thermo-mechanical fatigue damages.(2) The transformation was originated and developed with high anisotropy, being influenced by the following many factors : i.e., the strain field by the local plastic deformation, the crystallographic orientation, the re-heat treatment temperature and time, and the microsegregation in the material. The γ'-solvus in the reheating process drastically accelerated the local recrystallization.(3) The shearing of γ' precipitates in the straining process may play an intrinsic role in the cellular transformation : when the {111}<110> systems were activated, the formation was significant. When the {100}<110> slip systems were activated such as in creep failure at higher temperature, on the other hand, it was negligible.(4) The growth of the transformation was successfully represented by the Johnson-Mehl type equation. The growth of the transformation must be controlled by diffusion process of A1 and Ni, where activation energy was determined by about 36 kcal/mol.(5) The small fatigue crack propagation rate was remarkably enhanced at the transformed region. Less

本研究旨在弄清镍基单晶高温合金CMSX-2和CMSX-4局部塑性变形引起的异常组织或胞状转变的形成过程，为建立先进燃气涡轮机部件的修复技术提供基础性认识。在研究过程中，特别注意从晶体学和热力学的角度理解成核和生长行为。并探讨了变形与实际破坏损伤之间的关系。结果表明：（1）CMSX-2和CMSX-4在局部塑性变形损伤后，再经热处理，其胞状转变伴随着γ/γ'组织的片层或等轴状粗化，而在高温疲劳强度中，γ/γ'组织的胞状转变主要发生在γ/γ'组织中，胞状转变主要发生在γ/γ'组织中 ...更多信息 s起源。这不是一个特殊的现象，但它实际上是复制在材料受到疲劳和热机械疲劳损伤。(2)这种相变是在各向异性很强的条件下发生和发展的，并受到以下多种因素的影响：由局部塑性变形引起的应变场、晶体学取向、再热处理温度和时间以及材料中的显微偏析。再加热过程中的固溶线大大加速了局部再结晶。(3)应变过程中γ'沉淀的剪切作用可能在细胞转化中起着内在的作用：当{111}<110>系统被激活时，γ'沉淀的形成是显著的。另一方面，当{100}<110>滑移系统被激活时，例如在较高温度下的蠕变破坏中，它可以忽略不计。(4)用Johnson-Mehl型方程成功地描述了相变的增长。相变的增长受Al和Ni的扩散过程控制，其激活能约为36 kcal/mol。(5)在相变区，疲劳小裂纹扩展速率显著提高。少

项目成果

岡崎正和: "単結晶Ni基超合金のリサイクルおよびリコーティング支援"日本材料学会第48期学術講演会前刷. 105-106 (1999)

Masakazu Okazaki：“单晶镍基高温合金的回收和重涂支持”，日本材料学会第 48 届学术会议预印本 105-106 (1999)。

Masakazu Okazaki: "High Temperature Fatigue Small Crack Growth in Single Crystal Ni-base Superalloy with Locally Cellular Transformed Microstructure, (in Japanese)."Proc. 1999 Annual Meeting JSME/MMD, JSME. No. 99-16. 145-146 (1999)

Masakazu Okazaki：“具有局部胞状转变微观结构的单晶镍基高温合金中的高温疲劳小裂纹生长，（日语）”。

Masakazu Okazaki: "Strength of Ni-base Superalloy and the Refurbishment Technology, (in Japanese)."Proc. 48-th Annual Meeting, Soc. Mat. Sci., Japan, 11-15, (1999). J. Mat. Testing Asso. of Japan. 105-106 (1999)

Masakazu Okazaki：“镍基高温合金的强度和翻新技术，（日语）。”Proc。

岡崎正和: "単結晶Ni基超合金のリサイクルおよびリコーティング支援" 平成11年度日本材料学会学術講演会. 発表予定. (1999)

Masakazu Okazaki：“单晶镍基高温合金的回收和重涂支持”1999 年日本材料学会学术会议演讲（1999 年）。

Masakazu Okazaki: "Nucleation of Local Cellular Transformation in Single Crystal Ni-base Superalloy, (in Japanese)."Proc. 7-th Materials and Processing Conf., JSME. No. 99-23. 75-76 (1999)

Masakazu Okazaki：“单晶镍基高温合金中局部晶胞转变的成核，（日语）。”Proc。