Dual Intensity Peening and Aluminum-Bronze Wear Coating Surface Enhancement

Author:  WT Dingwell; AJ Lammas; H Halila, all of OH
Source:  US Patent 6,267,558 B1
Doc ID:  2001006
Year of Publication:  2001
Abstract:  
An article and a method for improving an article that results in a reduction or elimination of damage due to fretting from contact of similar metals. The invention specifically reduces wear-related fretting between titanium alloy parts by lowering the stresses between mating parts. An aluminum bronze coating is applied to one of the parts. The aluminum bronze coating provides an improvement over prior art coatings in reducing coefficient of friction between the parts. Additionally, the cumulative stresses at the surface of the parts is reduced by a dual intensity peening treatment. This involves a first peening operation using large peening media that provides a compressive stress to the required depth. This first peening operation is followed by a second peening operation that provides additional compressive stresses closer to the dovetail surface. The combined metallurgical and mechanical improvement results in a system with less susceptibility to fretting damage and corresponding improved fatigue resistance.