Copper and iron?

It was mentioned on wikipedia that iron-copper could work, but I couldn't get any effect. However I'm very lucky that one of my friends is in USA so he han purchase some of that lovely modules for me to experiment

powering them without cooling on the hotsides burns them out.
Of course, I even added some heatsinks to my ancient (tube) TV-s transistors cooling hot sides is not a big problem, have some ideas about that, for example simply attaching a CPU stock cooler or even water streaming down TEC-s hot surfaces