High cycle fatigue behavior of additively manufactured Ti-6Al-4V alloy with HIP treatment at elevated temperatures

The fatigue tests at 200 °C and 400 °C were conducted to investigate the elevated-temperature fatigue behavior of additively manufactured (AM) Ti-6Al-4V alloy with hot isostatic pressing (HIP) treatment. Since the manufacturing defects (i.e., pores) were significantly reduced by HIP treatment, no specimen failed from the pores. Consequently, the present AM Ti-6Al-4V alloy behaved superior to that without HIP treatment. Moreover, the specimens exhibited different failure mechanisms at 200 °C and 400 °C. Fatigue crack initiation at 200 °C mainly was due to surface deformation and strain localization, while the cause became fracture of surface oxygen-rich layer at 400 °C.