Layer wise evolution of the Cu-Zn alloy microstructure after sandblasting

This paper reports our recent studies on structural changes of a brass alloy (Cu-37Zn) after sandblasting. Investigation of the alloy foils using transmission electron microscopy (TEM) obtained at different distance from the treated surface. The existence of three structural surface layers after sandblasting was shown. The upper surface layer about 5 μm, corresponds to nano-crystalline state, the second one, consisting of nano-crystalline, ultra-microcrystalline and microcrystalline grains with FCC and orthorhombic structure mixture, occurs deeper than 5 μm and reaches the depth of 30 μm. The third layer can be attributed to the FCC disoriented cellular structure with multi-layer stacking-faults. The parameters characterizing changes of the nano-crystalline grains and polygonal structures are given. The role of the structural changes from one layer to another is discussed.