Tensile deformation-induced phase transformation and microstructural changes in a cast Zn-Al-based alloy (ZnAl7Cu3) were studied, using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microstructure of the cast alloy and various parts of the tensile tested specimens were detected. Two types of precipitates (alpha- and T'-phases) were observed in the Zn-rich phases, eta'(T) and epsilon, respectively. External tensile stress-induced phase transformation and microstructural changes were discussed. The fracture mechanism of the tensile deformed alloy was also discussed. (C) 2003 Elsevier Ltd. All rights reserved.