The trustees of the University of the District of Columbia voted last night to place a moratorium on the creation of any new graduate or undergraduate programs at the school until 1984.

The board approved the measure over the objections of some trustees that it would amount to a "no-growth policy" for the university and effectively "tie the hands" of the school's new president, Benjamin H. Alexander. Alexander has said frequently that he would like to start doctoral programs at the university.

But supporters of the measure argued that the school currently is in a critical period ofpreparation for completion of a new five-year master plan and its next evaluation by the Middle States Association--which accredits the school--and should therefore concentrate on improving its current programs.

Alexander said after the vote he was not disturbed by the measure because it contains a clause that would allow the trustees to approve a new program if "there is a demonstrative and compelling need."

The board also elected a new chairman, Ronald A. Brown, an attorney with the firm of Patton Boggs & Blow and deputy chairman of the Democratic National Committee. Brown served as board chairman from 1976 to 1980. He succeeds Marjorie H. Parker.

The board elected as vice chairman Estelle Taylor, chairman of the English department at Howard University. She succeeds Jesse L. King.