Raleigh made a whole bunch of those "technium" models. They are a bonded aluminum frame; that is, there are aluminum main tubes bonded to a steel rear end and BB shell/headtube.

This is a pretty good idea, it gives a bit of steel springiness in the rear end, and low overall weight.
I had one that I'd rebuilt, rode it for a couple of years. Quite decent, actually.

This one is one of the cheaper models with the headset-mounted shifters and all; I'm working on one of the nicer ones now with downtube shifters and aero brakes.

Looks to be in good shape, but they are old; make sure the wheel bearings and such don't need to be rebuilt.