Metalographic observation of cleaved grains in polycrystalline beryllium

In recent studies of cleaved grain densities in CIP/HIP P-1 beryllium, different densities were observed for the same amount of plastic deformation in samples prepared by two different metallographic procedures. One polishing procedure was exclusively mechanical while the other included a final etch-polish step. The reason for the difference in observed cleaved grain densities is addressed. Results showed that stress corrosion cracking in the presence of residual stresses and the etchant did not occur. The difference arose because some cracks were covered up during mechanical polishing