Al was introduced around the beginning of WWII here and dropped almost as soon as the war ended. By the late 1940s all electricians were back to copper. Therefore Al is fairly rare. Feeder-sized Al was re-introduced some time in the 1990s, usually 25 mm2 and up and mostly installed by utility companies rather than electricians.
Our neighbours behind the iron curtain used plenty of pure and copper-clad aluminium in all sizes, including even lacquered Al wire for transformers. Their Al conductors break easily when nicked but problems with expansion seem to be limited. Eastern Germany moved to crimp splices rather early, but in Hungary and Czechoslovakia mainly screw-type connectors were used for Al wire. I once had the chance to go through some old wiring in Prague checking all screws and the proportion of loose connections was no higher than in any copper installation I've encountered.
