Three-dimensional investigation of void growth leading to fracture in commercially pure titanium

TL;DR

This study visualized and analyzed the 3D growth of voids in pure titanium during fracture, revealing the influence of grain orientation and intervoid spacing on void growth and failure modes.

Contribution

It introduces a novel method combining femtosecond laser fabrication and X-ray tomography to study void growth in titanium, highlighting the impact of grain orientation.

Findings

Void growth aligns with Rice and Tracey model predictions.

Grain orientation significantly affects void growth.

Intervoid spacing influences ductile versus brittle failure modes.

Abstract

The fracture process of commercially pure titanium was visualized in model materials containing artificial holes. These model materials were fabricated using a femtosecond laser coupled with a diffusion bonding technique to obtain voids in the interior of titanium samples. Changes in void dimensions during in-situ straining were recorded in three dimensions using x-ray computed tomography. Void growth obtained experimentally was compared with the Rice and Tracey model which predicted well the average void growth. A large scatter in void growth data was explained by differences in grain orientation which was confirmed by crystal plasticity simulations. It was also shown that grain orientation has a stronger effect on void growth than intervoid spacing and material strength. Intervoid spacing, however, appears to control whether the intervoid ligament failure is ductile or brittle.