True Stress-Strain curve of metals

Hi everyone!

I was hopping to find some help over here. I just need some references or links to the true stress-strain curves of differents metals. I'm working with Tin and i'm going to do run some compression test to valid an analitic method. In order to do this, I need the strain-hardening exponent (n) and the strength coefficient (C) and it's being impossible to find those.

So, if anybody can point me in the right direction, any book, any webside, any program, with the true stress-straun curves whith wich I can deduce n and C, or any Table with these coefficients, I will be very grateful.

Thank in advance!