to hold the leaf spring in the flattened position when warmed in the subterranean location with heat h u2032 the element as before reverts to its manufactured shape and the spring acts to push out the central portion 16 to create or enhance the seal as another option for a biasing member 28 or 29 the material used can be a shape memory alloy fabricated for a long dimension and reformed above its transition temperature to a shorter length or extension when assembled to the mandrel 22 if used as a leaf spring 29 it can be reformed to flat before insertion in an annular space 34 or in the element 10 and before the element 10 has its outer dimension reduced using force f when at the subterranean location and heat in the form of h u2032 is delivered the biasing member reverts to its manufactured shape and original length and in so doing applies a force to the element 10 to create or enhance the seal if used as a leaf spring the manufactured shaped can be bowed and then it can be heated and reshaped above its transition temperature and inserted in space 34 or within the element 10 itself at the subterranean location the applied heat h u2032 will cause.