Martin Marietta Corp., a diversified aerospace, aluminum and construction materials firm based in Bethesda, plans a record $213 million in capital expenditures next year.

In addition, president Thomas G. Pownall told the Washington Society of Investment Analysts yesterday, his firm expects to report record profits for 1977 and performances in its five divisions the next 12 months that point to continued expansion of both sales and profitability.

The decision to expand new facilities at a record rate comes a ta time when govenment economists have been concerned about sluggish capital outlays for American business in general.

But Pownall said yesterday that Martin Marietta's own spending plans, up from $150 million in the current year, are expected to continue to expand in the next couple of years.

"I don't buy the general philosophy . . . that the U.S. is flat on its back," he said. "We don't know of a better place to invest than the U.S. and nothing will be cheaper than today," the Martin Marietta officer said, in response to a question.

"Unless you know business will be rotten," said Pownall, spending now will bring about facilities needed in the future. In the case of Martin Marietta, he continued, growht expected in all divisions warrants the bullish spending.

Specifically, Pownall said his firm plans initial work for a new cement plant in Davenport, lowa, to cost up to $80 million; expansion of an alumina plant in the Virgin Islands, and expansion of primary aluminum capacity as well as aerospace operations.

Up to 50 per cent of next year's outlays will be for replacement of existing facilities. All of the funds will be generated without new long-term debt. The company does not include any major acquisition in the spending forecast, Pownall added.

Martin Marietta has continued to look about for possible aaquisitions and could respond to any attractive situation, but has decided to concentrate on building its won resources, he said.

Profits for 1977 could reach the $100 million level compared with $78.5 million last year, with sales up 10 per cent to about $1.45 billion. Earnings and sales are up in all of the five company divisions - aerospace, cement, aggregates, chemicals and aluminum.

On Nov. 17, Martin Marietta boosted its quarterly dividend rate for the second time this year, to a $1.60 annual rate. Pownall said yesterday the payout rate probably would be studied by directors again at meetings early in 1978.