The Morphological Properties and Microhardness of As-Cast and Melt-Spun Al-5Zn-2.5Mg Alloy

The morphologics and microhardness properties of the conventional solidified Al-5Zn-2.5Mg alloy was obtained by casting 99.99% pure Al, Zn and Mg by using a vacuum furnace and then the rapidly solidified ribbons specimens for the same alloy that was produced by using the melt-spinning technique with different wheel speeds of (10, 50 and 80)m/s. These samples have been studied by using the scanning electron microscopy, X-ray diffraction, differential thermal analysis, Vickers microhardness tester with various peak loads at room temperature. Moreover, the conventional solidified and the rapid solidified samples have been tested under a universal testing machine for the tensile tests. The scanning electron microscopy analysis shows that the conventional solidified samples have a dendritic -Al solid solution and non-equilibrium phases. The X-ray diffraction patterns for the conventional solidified samples revealed three phases namely, two intermetallic phases (Al12Mg and MgZn2) and the -Al phase. While no peaks corresponding to the intermetallic phases for the rapid solidified ribbons obtained by 50 and 80m/s wheel speeds. The melting temperature for the rapid solidified ribbons of 10, 50 and 80m/s wheel speeds were 660, 660 and 662 degrees C, respectively. The tensile stress curves show that there are huge enhancements in the rapid solidified samples than those in the conventional solidified samples.