In this study, an investigation is carried out to evaluate and compare the material and physical properties of Grade 5 Titanium alloy (Ti6Al4V G5) samples of three different impeller manufacturers. The study aims to identify the efficient impeller core material from different Ti6Al4V G5 manufacturers. Ultrasonic fatigue test for Ti6Al4V samples of 100 horsepower (hp) centrifugal compressor impeller parts is performed before and after heat treatment. The effect of microstructure on Very High Cycle Fatigue (VHCF) behavior of Ti6Al4V is also analyzed and discussed in detail. Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) observation are carried out to investigate the microstructure of different Ti6Al4V material samples. The dynamic elastic properties are measured by the Impulse Excitation Technique (IET) at room temperature. The fracture behavior of the tensile specimens is analyzed by SEM. Post-heat-treatment analysis of Ti6Al4V is also carried out and presented which affects the grain size of the material sample and thus considerable effect in the mechanical properties. Chemical composition investigation of Ti6Al4V using SEM and Energy Dispersive X-ray Spectroscopy (EDS) also included in this study.
Keywords: S-N curve; Ti6Al4V; VHCF; heat treatment; microhardness; microstructure; ultrasonic fatigue test.