Microstructural Evolution
Characterization and Degradation Evaluation of Areo-engine used Superalloys
after Suffering Overheating
C.K.
Liu*，W.X.
Zhao，J.Y. Zhou，Z.
Zheng，W.J. Xing
AVIC
Beijing Institute of aeronautical materials, Beijing, 100083, China
ABSTRACT: Nickel-based superalloys
are widely used for aero-engine turbine blades and disks, which are subjected
to complex elevated temperature and stress couplings during long-time service.
Overheating often occurs due to operation accidents such as engine surge or
erroneous operations, which may lead to serious microstructural degradation or
even premature failure of turbine blades and disks. This study characterizes
the microstructural evaluation microstructural characterization and degradation
evaluation of various Nickel-based superalloys after overheating service,
including single crystal directionally solidified, and powder metallurgy
superalloys.Three aspects are introduced: (1) by using neutron scattering and
synchrotron radiation technologies, microstructure characteristics, element
segregation behavior, lattice mismatch of γ and γ’ phases, stress rupture
properties of single crystal superalloy are investigated. In addition, microstructure
characteristics, lattice mismatch of γ and γ’ phases, precipitation behavior of
secondary phases at different locations of directionally solidified turbine
blades are studied. (2) Long-term microstructural stability and physical
properties (such as density, sound velocity, modulus) of powder metallurgy
superalloy are investigated during thermal exposure at 650 °C or with 900 MPa
stress. The microstructure characteristics of the main strengthening phase γ’
phase are systematically characterized, the quantitative parameters including
area fraction, equivalent diameter and shape factor are used. (3)
microstructural degradation of DZ408 and IC10 superalloys after suffering
overheating are revealed by overheating simulation experiments, criterion of microstructure
characteristics and overheating microstructure atlas are established, and the
engineering application is introduced.
Keywords: Casting superalloy; powder superalloy; microstructural evolution; overheating; service
C.K.Liu, Doctor of Engineering, Researcher, Doctoral Supervisor. Served as the deputy director of the Testing Center of the Beijing Institute of Aeronautical Materials of China Aviation Development, the head of the Aviation Industry/China Aviation Development Failure Analysis Center and the COMAC Mechanical Failure Analysis Center, the director and director-general of the Failure Analysis Branch of the Chinese Society of Aeronautics, 《Failure Analysis and Prevention》Editor in chief. Mainly engaged in metal material detection and characterization, material and structural damage and failure analysis and life prediction, etc., responsible for and participating in more than 30 topics such as national defense technology foundation, aviation key models, major national defense projects, major consulting projects of the Chinese Academy of Engineering, and published academic. There are more than 70 papers, 4 books published, 5 authorized patents, 2 second prizes of provincial and ministerial level science and technology, 3 third prizes, and 2 third-class models.