The angular distributions of atoms sputtered from pure Cu and Be as well as Cu98Be2Cu71Zn29Co3Au, and WSi2 3were investigated for bombardment with Ar +ions of 250 eV and 2 keV under normal incidence. Between polar emission angles θ — 0° and 60°, for the higher bombarding energy all observed angular distributions look very much alike and follow essentially a cos3 θ law. For the low bombarding energy, however, significant differences between the angular distributions of the alloy constituents are found. The effect, which is most pronounced for CuBe, seems to scale with the atomic mass in the way that the lower mass particles are sputtered preferentially along the surface normal. © 1988, American Vacuum Society. All rights reserved.