Performance Assessment of a new Ceramic Medium for Use in an Improved Aircraft Structures Shot-Peening Process: Evaluation of Fatigue Life Enhancement****

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Curtiss-Wright Surface Technologies is an industry leader in shot peening, a cold working process in which small spherical media called shot bombard the surface of a part. Traditionally the aircraft industry has used shot peening in accordance with Aerospace Material Specification (AMS) 2430 using AMS 2431/1 or 2431/2 to shot peen components. The purpose for shot peening is to improve fatigue life and stress corrosion resistance by imparting compressive stresses on the part surface. Although many different media exist to perform this process (i.e. blast small objects at parts to plastically deform the surface), the industry has classically used AMS 2431/1 or AMS 2431/2 cast steel shots. These shot media have finite life, pollute the component surface, create health and safety issues as they decay and require disposal. Recently the shot media industry has developed a new ceramic shot that alleges to meet the criteria above. The shot is in the marketplace, however, has yet to be technology demonstrated (TRL 4-6) to be industrially accepted nor qualified for airworthiness. This proposal seeks to partially address this issue by conducting a characterization study aiming at assessing the performance of the new ceramic medium, in particular in as far as improvement in fatigue life is concerned.**Curtiss Wright Metal Improvement Company (CW MIC), a division of Curtiss-Wright Surface Technologies, has a major shot peening facility in Brampton Ontario. The industrial qualification of the proposed shot peening medium is of particular interest to the Brampton facility, hence the interest in this proposed collaboration. The successful completion of this demonstration program would provide benefits to Curtiss Wright MIC by paving the road for a major qualification effort of the new ceramic shot medium, aiming to improve component performance, improve the life cycle cost of shot media, eliminate decontamination, reduce dust exposure to employees and provide a cradle to cradle environmental solution to shot media.****