A method of controlling bulk absorption of atomic hydrogen and facilitating degassing of hydrogen from aluminum alloy workpieces during heat treatments in furnaces with ambient and/or moisture-laden atmospheres by exposing the surface of the workpieces to a low molecular weight solution or dispersion of an alkyl phosphonic acid, an olefinic phosphonic acid or an aryl phosphonic acid before subjecting the workpieces to heat treatments. The workpieces exposed to the phosphonic acid solution or dispersion are subjected to heat treatment in furnaces having ambient or moisture-laden atmospheres. The solution or dispersion involves chemical species that are deposited onto the aluminum surface from the phosphonic acid solution or dispersion which substantially decrease the amount of atomic hydrogen entering the bulk of the workpieces from their surfaces during heat treatment and, in addition, facilitate removal of atomic and molecular hydrogen from the bulk of the workpieces during heat treatment.