Surface modification and repair for aircraft life enhancement and structural restoration

Maintenance of ageing military aircraft structures encompasses both engineering and scientific management. In support of this, surface modification and repair methods are used on an opportunity basis to extend the life of aircraft in terms of fatigue and safety. Often, certain surface modification technologies have proved to be both cost effective and amenable for safe application. Some candidate technologies include shot peening, cold spray, deep surface rolling, friction stir welding, laser shock peening, and laser cladding. Whilst some technologies have been successfully applied to Australian Defence Force (ADF) aircraft in the past, some newer technologies are also being considered. The supersonic particle deposition (SPD) technology also known as cold spray coating has been recently approved for application on a helicopter gear box. Another technology of significance to ADF application is Laser Cladding (LC) technology. This paper briefly summarises the research work on these technologies at DSTO and discusses potential applications for aircraft components in the near future. It also provides an analysis of technologies and their potential advantages and disadvantages.