Microstructural Restoration by HIP and Heat Treatment Processes in Cast Nickel Based Superalloy, IN-738

作者：Wangyao Panyawat; Lothongkum Gobboon; Krongtong Viya****; Homkrajai Weerasak; Chuankrerkkul Nutthita^*

来源：Chiang Mai Journal of Science, 2009, 36(3): 287-295.

• hot isostatic pressing (HIP)
• rejuvenation
• microstructural repair
• nickel-based superalloy

Inconel 738, as a cast nickel-based superalloy components for land-based gas turbine blades, utilized at elevated temperatures, expresses, microstructural stability with excellent mechanical properties. In this study, the microstructural refurbishment by a hot isostatic pressing (HIP) and different heat treatment conditions after long-term service of the alloy was investigated. Although, the HIP temperature in the HIP process was high enough to act as solutioning treatment, it could not completely dissolve coarse gamma' particles into the matrix, resulting in the residue particles. However, the nest step, solutioning treatment, could dissolve these particles more in some extent depending on each solutioning temperature. The higher solutioning temperature provided the finer gamma' particles and new gamma' precipitation after solutioning that could take place during primary aging. Secondary aging led to the growth of coarse and/or very fine gamma' particles. All heat treatment conditions after HIP process provided much more uniform gamma' morphology comparing to as-received microstructure.

• 出版日期2009-9