American Federal Savings and Loan Association of Washington announced this week that it has placed $11 million in mortgage-backed bonds to help originate home mortgage loans in this area.

The bonds were placed with a consortium of institutional investors headed by Aetna Life Insurance Co. of Hartford, Conn., according to R. H. Sinclair, chairman of the board of American Federal.

Mortgage-backed bonds, obligations in which mortgages are used as collateral, are a relatively new way for financially pressed lenders to raise money to make mortgages. American Federal's bonds were issued at an interest rate of 10 1/8 percent with a Triple A rating from Standard & Poor's rating service, Sinclair said.

American already has $6 million in home mortgage commitments for properties in the District and the suburbs, a spokesman said.

Earlier this week, Washington's Perpetual Federal Savings and Loan Association, in a move to pump an additional $150 million into the area's tight mortgage market, issued $25 million in unsecured notes. Perpetual was one of the first S&LSs in the country and the first in the Washington area to issue unsecured notes, which were authorized six months ago by the Federal Home Loan Bank Board.