The United States team, winless and in last place after five games in the World Ice Hockey Championships, smoothed over dissension in the ranks yesterday by replacing Coach Johnny Mariucci.

Herb Brooks, the designated coach for the U.S. Olympic team and head coach at the University of Minnesota, will take over from Mariucci for the last five games.

In action yesterday, the Soviet Union, led by Vladimir Golikov's two goals, flattened Sweden's nervous favorites, 6-1.

The Swedes, overcautious after a prechampionship loss to the Soviets in Stockholm, did not score until Kent-Erik Anderson connected at 1:33 of the third period.

In the second game, Czechoslovakia hammered Canada, 5.0, despite a heroic goal defense by Dan Bouchard of the Atlanta Flames, ending Canadian hopes of finishing among the top four teams in the world championships.

Czechoslovakia took the lead in the first period when left wing Jaroslay Pouzar scored a shorthanded goal.The Czechs gained clear superiority in the second period but could slip only one of their barrage of 34 shots past Bouchard.

Bouchard performed outstandingly against the rampaging Czechs in the final period, but couldn't stop goals by Jiri Novak, Peter Stastny and Frantisek Cernik.