re your comment
I live at 6,000 feet above sea level. It takes me longer to
boil and bake things. Is it possible that annealing and other
heating procedures would be affected by this altitude? Would they
be slower? Or am I just imagining things?
The question takes me back to grade 12 physics
P1T1=P2T2. If you were able to create a vacuum, you could find that
water would boil at room temperature, say 20 deg C. Things don't
cook very well at that heat. Alternatively, if you use a pressure
cooker and not let the water boil at standard atmospheric pressure
then the water temperature must rise to boil. I've been told that
mountain climbers bring along small pressure cookers so that at high
altitudes they can cook the food.
So what we are talking about is the boiling point of liquids. The
boilling points of gold silver and copper are respectively 2,807,
2,212, & 2,567 deg C respectively; values so high that a change in
pressure lowering the bp is marginal.
Thus the question now is does the lower pressure influence the
formation of large crystals from small crystals. Given the relative
high melting points of the metals, it's unlikely or at least
marginal. But I could be mistaken.