Heating that occurred during argon-ion bombardment of a thin film of a quasicrystalline phase of an Al─Li─Cu alloy resulted in distortion and subsequent phase transformation. The distortion causes staggering of the diffraction spots in the fivefold symmetry as well as contraction and expansion of the systematic rows parallel to the axis of the symmetry of the distortion which is one of six fivefold axes. The results support the quasicrystalline model of the icosahedral phase which transforms possibly to a cubic phase through an intermediary metastable configuration corresponding to the distorted phase.