Effects of ion implantation of 320 keV28Si at room temperature in pseudomorphic metastable GexSi1−x(x≊0.04, 0.09, 0.13) layers ∼170 nm thick grown on Si(100) wafers were characterized by x‐ray double‐crystal diffractometry and MeV4He channeling spectrometry. The damage induced by implantation produces additional compressive strain in the GexSi1−xlayers, superimposed on the intrinsic compressive strain of the heterostructures. This strain rises with the dose proportionally for doses below several times 101428Si/cm2. Furthermore, for a given dose, the strain increases with the Ge content in the layer. Upon thermal processing, the damage anneals out and the strain recovers to the value before implantation. Amorphized samples (doses of greater than 2×101528Si/cm2) regrow poorly.