High-Strength Al-Zn-Cu-Based Alloy Synthesized by High-Pressure Die-Casting Method

High-strength alloys of Al- x Zn-3Cu ( x = 20, 30, 40 wt pct) are developed for die-casting process. The maximum tensile strength of the developed alloy is 435 MPa, with a stain to fracture of 4 pct. Microstructural investigation shows that the grain size of α -Al gradually decreases and the area of the Zn-rich region increases as the amount of Zn increases. Local symmetry investigation reveals that the major phase of α -Al contains very fine nanoprecipitations of Zn phase (<10 nm), with a very small amount of strain along 1 1̅ 0. In addition, the Zn-rich region of the grain boundary has a very complex microstructure. This study discusses the effect of the microstructure of the developed Al alloys on the mechanical properties.