Rc. Muthiah et al., A STUDY OF DYNAMIC EMBRITTLEMENT IN BICRYSTALS OF CU-7-PERCENT-SN, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 234, 1997, pp. 1033-1036
In a kinetic model [1] for the phenomenon of dynamic embrittlement, th
e cracking rate is predicted to be proportional to the diffusivity of
the embrittling species along the grain boundary. To test this model,
bicrystals of Cu-Sn with Sigma 5 symmetrical tilt boundaries in which
tin is the embrittling element are being used. The diffusivities paral
lel and perpendicular to the tilt axis are expected to be different, t
herefore, the crack growth rates in these two directions should Vary i
n the same ratio as the diffusivities. Measurements of the crack-growt
h rate along the [100] direction in the Cu-Sn alloy bicrystal at 265 d
egrees C showed that the cracking occurred by decohesion along the gra
in boundary with almost no observable plasticity at a maximum crack gr
owth rate of approximately 10(-6) m s(-1). A model for steady-state cr
ack growth has recently been developed and is discussed here. (C) 1997
Elsevier Science S.A.