Strain rates (Creep Strain)?

The atoms and,more importantly,the crystal defects become more mobile with increasing temperature ;especially with lead/tin solder which has a eutectic temperature at 183 deg C which essentialy means that in highly stessed areas like grain and interfacial boundaries the local structure would constitute a viscous liquid.Some superplastic alloys actualy refine their structure under working conditions that resemble high speed creep.