Hi. I hope that 'Physics' is the most appropriate category for this,
if not please pass on to 'Technology':

I'm experimenting with bismuth-tin alloys. These low melting point
metal alloys (they melt upwards from 138degC or so) expand on
solidification and can be used to form simple plugs in small bore
steel pipes.  However, at temperature (80degC) and under the combined
compressive force of the pipe's hoop stress and applied hydraulic
pressure, the plug will creep and leak.
 
So the questions are these if I may: 1. Where can I find compressive
creep test information for bismuth? and 2)What equations should I use
to estimate how fast a bismuth-tin plug in a steel pipe will creep at
applied pressure and temperature?  

I feel that the situation is quite complex since the plug may try and
flow like a super-viscous fluid rather than move down the pipe like an
ultra-slow slow airgun pellet!  I'd be delighted to have an answer. 
With kind regards.