MODELING INTERGRANULAR FRACTURE AT ELEVATED TEMPERATURE

This project aimed to produce numerical models for intergranular fracture at elevated
temperature as continuation of the work by Rishi Raj and M.F. Ashby [1]. They have
been studying about intergranular fracture caused by void formation mainly on
homogenous copper. As one of the most referred journal in intergranular fracture at
elevated temperature, working numerical models on other materials have not yet
been made available. Upon completion of the numerical model, it will be then
applied to other materials and applications that are exposed to intergranular fracture
at elevated temperature. This project is divided in two main sections; to build a
numerical model for nucleation of voids and the growth of voids. Even though there
are many types of creep failures, the project will be centered only on creep failure as
a result of nucleation, growth and coalescence of voids. The work will reproduce the
model of nucleation and growth based on copper data as in the work of Raj and
Ashby [1] and then to apply the models to other materials. It is anticipated that with
the nucleation and growth models, estimation of rupture time of a material at
elevated temperature can be reliably predicted. It is important not to confuse between
intergranular fracture caused by void nucleation, growth and coalescence and
intergranular fracture caused by boundary cracking. Major difference between these
two is intergranular fracture caused by void formation occur in low stress, elevated
temperature environment whereas intergranular fracture caused by boundary
cracking is due to high stress exerted to the material.