Ys. Zhang et Gc. Stangle, A MICROMECHANISTIC MODEL OF THE COMBINED COMBUSTION SYNTHESIS-DENSIFICATION PROCESS, Journal of materials research, 10(7), 1995, pp. 1828-1845
A series of computer experiments has been conducted in order to study
the combined combustion synthesis-densification process, in which a me
chanical load is applied to a sample as it undergoes a combustion synt
hesis process. The current work is an extension of a theoretical model
of the combustion synthesis process that was developed previously.(1.
2) In this work, the appropriate constitutive equations for sample def
ormation have been incorporated, in order to account for the pore-volu
me change that mag take place when the mechanical load is applied, thu
s densifying the sample. It was shown that the brief appearance of a l
iquid phase in the combustion wave front provide:, an important opport
unity for densification when the self-propagating combustion synthesis
process is conducted in conjunction with an applied mechanical load.
That is, the concomitant decrease in the (local) total volume fraction
of the solid phases-due to the elementary melting and dissolution pro
cesses that also occur (locally)-effectively lowered the (local) appar
ent yield strength of the sample, thus allowing for the compaction and
densification of the sample (i.e., locally). Results indicated that t
he mechanical load should be applied at the instant at which the sampl
e is ignited, in order to ensure that articles whose density is unifor
m throughout the sample can be fabricated, This work provided a more d
etailed and quantitative understanding of this unique process for prep
aring dense articles by the self-propagating combustion synthesis proc
ess. that ist when it is conducted in conjunction with an applied mech
anical load.