Microstructures and Mechanical Properties of Hot Isostatic Pressed Parts of Ti-6Al-4VELI Alloy Spherical Powders with Three Different Diameter Distributions

We report the microstructure and mechanical properties of Ti-6Al-4VELI (extra low interstitial) alloy parts fabricated with three diameter distributions of Ti-6Al-4VELI spherical powders by hot isostatic pressing (HIP), which were manufactured via plasma rotating electrode processing (PREP). The powders were canned and pressed at temperatures 940 °C and pressure 120 MPa. α+β mixed phases in the specimens were observed through Optical Microscope (OM), Scanning Electron Microscopy (SEM) and energy dispersive spectroscopy (EDS) methods. The results show the microstructures of specimens are found to be strongly dependent on the different distributions of powders. The samples formed from fine powders (45∼100 μm) shows better microstructure properties than those formed from medium powders (100∼150 μm) and coarse powders (150∼250 μm). In addition, the billets formed from fine powders exhibit higher tensile strength and ductility than those formed via medium powders and coarse powders. These results are attributed to the initial microstructures of HIP samples, as confirmed by evaluating their fracture features.