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In situ straining TEM observation of fracture behavior in PST crystals of TiAl

Book ·
OSTI ID:72516
; ;  [1]
  1. Shanghai Jiao Tong Univ. (China). Dept. of Materials Science
Crack propagation process in TiAl alloy PST crystal has been investigated by in situ straining TEM observation. It has been found that the influence of lamellar boundaries on the fracture behaviors is connected with the types of interfaces (twin, pseudo-twin and {alpha}{sub 2/{gamma}} interfaces). Even though secondary microcracks always nucleate at {alpha}{sub 2}/{gamma} interfaces due to stress concentration, the crack growth is cleavage in {alpha}{sub 2} and {gamma} phases rather than along interlamellae. When a crack meet {gamma}/{gamma} interfaces, its propagation can be inhibited and crack tips blunt by the slide of the interfaces. It also deserves to be mentioned that ductility of PST crystals has connection with the rate of crack propagation.
OSTI ID:
72516
Report Number(s):
CONF-941144--; ISBN 1-55899-265-0
Country of Publication:
United States
Language:
English