Breakthrough in Anti-Fatigue 3D-Printed Titanium Alloy by Chinese Scientists

A research team from the Institute of Metal Research of the Chinese Academy of Sciences, led by Professors Zhang Zhefeng and Zhang Zhenjun, has made a significant breakthrough in enhancing the fatigue resistance of 3D-printed titanium alloys. Their study, recently published in the journal Nature, introduces an innovative approach known as Net-Additive Manufacturing Preparation (NAMP) that improves the material's endurance under cyclic loading—a critical factor for its application in demanding fields like aerospace and space exploration.

The poor fatigue performance of materials produced through Additive Manufacturing (AM), or 3D printing, has historically limited their use in structural components where durability under repeated stress is essential. The researchers attribute this limitation to microvoids introduced during the printing process, which detract from the inherent fatigue resistance of the material's microstructure.

To address this issue, the team developed the NAMP process, which consists of hot-isostatic pressing (HIP) to eliminate these detrimental microvoids, followed by a high-temperature-short-time (HTSt) heat treatment. This treatment restores the AM microstructure characterized by fine martensite lath, resulting in a titanium alloy with a nearly void-free Net-AM microstructure and exceptionally high fatigue resistance.

Remarkably, the Net-AM microstructure demonstrates superior fatigue resistance compared to both other 3D-printed and traditionally forged titanium alloys. It also boasts the highest specific fatigue strength (fatigue strength divided by density) reported worldwide. The study found that fatigue cracks in microstructures produced through NAMP typically originate at clean primary β grain boundaries and fine martensite lath, avoiding traditional fatigue weaknesses and preventing localized damage accumulation.

This groundbreaking study not only underscores the natural fatigue resistance of 3D-printed microstructures but also highlights the potential of 3D printing technology in creating structural components with enhanced durability. The findings of Professors Zhang Zhefeng and Zhang Zhenjun's team offer a promising direction for manufacturing anti-fatigue materials through additive manufacturing processes.