The two parts have axial symmetry right?
Have you considered Friction welding the two parts together?
http://www.youtube.com/watch?v=cAXZYGZ8Yrg
Apparently the friction welding process does a good job of welding differing metals together too. Here’s a video of connecting aluminum to copper:
http://www.youtube.com/watch?v=2oAWQd2_dz8
I’m no mechanical or materials engineer, but the process seems like it might be worth looking into…
Cheers,
-S
