J. Mater. Sci. Technol. ›› 2021, Vol. 73: 193-204.DOI: 10.1016/j.jmst.2020.09.035

• Research Article • Previous Articles     Next Articles

Microstructural evolution and tensile property of 1Cr15Ni36W3Ti superalloy during thermal exposure

Haoze Lia,b, Ming Gaoa,b, Min Lic, Yingche Maa,b,*(), Kui Liua,b,*()   

  1. aCAS Key Laboratory of Nuclear Materials and Safety Assessment, IMR(NMSA), Shenyang 110016, China
    bShi-changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, China
    cCollege of Material Science and Engineering, Shenyang Areospace University, Shenyang 110136, China
  • Received:2020-07-06 Revised:2020-08-18 Accepted:2020-08-28 Published:2021-05-20 Online:2020-09-30
  • Contact: Yingche Ma,Kui Liu
  • About author:kliu@imr.ac.cn (K. Liu).
    *CAS Key Laboratory of Nuclear Materials and SafetyAssessment, IMR(NMSA), Shenyang 110016, China.E-mail addresses: ycma@imr.ac.cn (Y. Ma),


1Cr15Ni36W3Ti was thermally exposed at 580 ℃ and 680 ℃, respectively, up to 3000 h. The γ’ phase and intergranular TiC carbides continuously coarsened during exposure. None of η, laves or σ phase was discovered in the exposed samples, indicating good microstructure stability under the present exposure conditions. The ripening process of the γ’ phase could be well modelled utilizing the LSW theory. The evolutions of the yield and tensile strengths were monotonous during exposure at 580 ℃. However, a transition point in strengths was detected in the tensile samples exposed at 680 ℃ for 300 h. Accordingly, the critical γ’ diameter was measured to be 13-14 nm. The γ’/dislocations interaction mechanism transformed from shearing to looping with the γ’ diameter exceeding the critical point. The combination of the weakly coupled dislocations model and the Orowan looping model yielded a critical diameter of 13.1 nm which coincided well with the measured one, indicating the applicability of these two strengthening models for 1Cr15Ni36W3Ti. The present exposure conditions did not exert a profound effect on the fracture mode. All the tensile samples underwent a typically ductile fracture with a dimple pattern dominating the fracture surface. The dispersed deformation induced by the prevalence of dislocation looping in the over-aged tensile samples retarded the propagation of intergranular cracks. The declined precipitation hardening increment and the enhanced deformation homogeneity partially recovered the tensile ductility in the over-aged samples exposed at 680 ℃.

Key words: Superalloy, γ' Phase, Thermal exposure, Microstructure, Tensile property, Fracture