OPTIMIZING THE MECHANICAL PROPERTIES OF TI-6AL-4V CASTINGS

The use of Ti-alloys in the as-cast condition leads to a considerable savings in the manufacturing costs. This study aimed at optimizing the mechanical properties of Ti-6Al-4V castings through studying the effect of different pre-designed heat treatment cycles on the microstructure and mechanical properties of cast Ti-6Al-4V alloy. The design and selection of the heat treatment cycles was made after determination of the transformation temperatures of the alloy, β-transus (Tβ) and martensite start transformation (Ms) temperatures. The alloy was characterized before and after heat treatments using microstructural investigation in addition to tensile and Charpy impact toughness tests. The fracture surfaces of the broken impact samples were investigated using Scanning Electron Microscope (SEM). Finally, the relation between the heat treatment, microstructure and mechanical properties of Ti-6Al-4V cast alloy was established and the optimum heat treatment cycle that optimized the mechanical properties was selected.