Review of directed energy deposition additive manufactured printed specimens

• Main Author: Yusuf Bin Mohd Azawan
• Other Authors: Pang Hock Lye, John
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; Additive manufacturing; DED; Fatigue
• Online Access: https://hdl.handle.net/10356/176827
• Institution: Nanyang Technological University

This Final Year Project (FYP) paper presents a comprehensive study on the fatigue behaviour of Directed Energy Deposition specimens on these 5 commonly used materials - Stainless Steel 316L (SS316L), Titanium Alloy (Ti-6Al-4V), Aluminium Alloy (AlSi10Mg), Inconel 625 (IN625), Inconel 718 (IN718). The focus is on two key factors influencing fatigue life, which is process parameters (including post-processing) and microstructure. Fatigue data, process parameters and microstructure were compiled from literature reviews. Common attributes and correlations with fatigue behaviour are analysed. Process parameters analysed included the effects of laser power, scan speed, interlayer treatments, while microstructure analysis included the porosity and surface defects. This study reveals a lack of standardisation in documenting and understanding the relationship between process parameters and reproducing similar or consistent fatigue performance. Computational modelling has not matured enough to comprehensively predict and map the relationship between fatigue and DED process parameters. The findings of this FYP provide valuable insights into the potential to harness DED in more application and robust usage in the additive manufacturing industry, especially in fatigue-critical applications and the need for process optimization to minimize defects.