An investigation of fatigue of additively manufactured commercially pure Alpha–Ti alloy at 350 °C

Abstract

This work presents an elevated temperature fatigue study on additively manufactured (AM) commercially pure (CP) alpha Ti alloy with dispersed TiB particles. This study consists of both experimental and analytical investigations. Experimental data presented in this work were collected using a rotating beam fatigue (RBF) tester and a scanning electron microscope (SEM). The experimental findings presented in this work show that the AM Ti–TiB alloy lost its fatigue strength considerably at 350 °C compared to its reported room temperature fatigue strength. This loss in fatigue life is attributed to the numerous surface crack propagations. Moreover, a novel modification to the Paris’ law equation is introduced in this study. This modified equation is designed to predict fatigue life under elevated temperatures, especially in scenarios involving extensive major crack propagation. Notably, this modified equation improved the fatigue failure prediction accuracy, measured in terms of R2 value from 0.34 to 0.93.

Keywords

• Additive manufacturing
• Fatigue
• Alpha Ti–TiB
• High temperature
• Paris′ law