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Effect of cooling rate on microstructure and mechanical properties of K465 superalloy

  • Zhong-ye Pei
  • Wei Han
  • Gang Zhao
  • Xing-fu Chen
  • Jun-tao Li
  • Yan-wen Tian
Article

Abstract

K465 superalloy, as a material for production of turbine nozzle, shows high mechanical properties as well as microstructure stability under critical and severe service conditions. The appropriate microstructure and strength of this alloy can be obtained by solid solution strengthening mechanism. Heat treatment parameters such as time and temperature of homogenization, partial solution and aging temperatures, and cooling rate from solid solution temperature affect the microstructure of the alloy. Among these parameters, cooling rate from solid solution temperature is the most effective. Therefore, the effect of cooling rate on microstructure and mechanical properties (tensile and stress properties) was investigated. For this purpose, three different cooling rates were applied to the cast K465 specimens subjected to solution treatment at 1 483 K for 4 h. Microstructures of the specimens then were studied using optical and electron microscopy. Also, tensile tests were performed at room temperature and stress rupture tests were performed under the condition of 1 248 K and 230 MPa. It was found that with increasing the cooling rate, the size of the γ’ precipitates decreases and the mechanical properties of specimens increases. Also, it was found that the shape and volume fraction of primary γ’ particles are largely influenced by the cooling rate after solution treatment at 1 483 K for 4 h.

Key words

cast superalloy solution heat treatment cooling rate microstructure mechanical property 

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Copyright information

© China Iron and Steel Research Institute Group 2009

Authors and Affiliations

  • Zhong-ye Pei
    • 1
    • 2
  • Wei Han
    • 2
  • Gang Zhao
    • 2
  • Xing-fu Chen
    • 2
  • Jun-tao Li
    • 2
  • Yan-wen Tian
    • 1
  1. 1.School of Material and MetallurgyNortheastern UniversityShenyang, LiaoningChina
  2. 2.High Temperature Materials Research DivisionCentral Iron and Steel Research InstituteBeijingChina

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