Laser metal deposition repairs – Dr Shi Da (Stephen) Sun

Laser metal deposition repair for aircraft landing gear component – RMIT University

Dr. Stephen Sun was awarded his PhD in 2014. Stephen’s research explored the possibility of implementing laser powder deposition (LMD) to repair ultra-high strength steels in fatigue critical load carrying aerospace components, such as aircraft landing gear. The main objectives of his work were to assess the microstructure, fatigue and mechanical properties of the as-clad, and then compared the results to the substrate base-line condition. The key highlights of this research were developing a processing strategy to successfully re-build geometry using LMD with a defect free clad layer and a small Heat-affected Zone and improved mechanical and fatigue material properties. The results showed that LMD offers a very promising path to restore and possibly increase the structural integrity of damaged ultra-high strength steel components.

The research was part of a larger project: Project 4.1 – Repair Technologies for Current and Next Generation Aircraft Systems. This project investigates the feasibility of restoring a range of aero components which suffer damage exceeding permissible limits, to the required minimum level of performance using LMD. Dr. Sun was the lead investigator into the repair of steels.

Dr. Sun is continuing his research at the RMIT Centre for Additive Manufacturing as a LMD specialist. His career aspiration focuses on developing LMD technology for industrial collaborations in additive manufacturing and repair of high valued, complex mining and aerospace components. The goal is to combine research and process development to allow users to maximise the useful service life of costly parts, and component replacement may be avoided, together with the associated loss of availability.