Statistical Analysis of Titanium Alloy Surface Processing on Aerospace Components Strength

Abstract

In the aerospace and space industry, Titanium alloys such as Ti-6Al-4V and their surface processing are widely used due to their excellent strength and lightweight characteristics such as their high strength-to-weight ratio, excellent corrosion resistance, and many factors. It is well known that the tested strength of aerospace components, such as fasteners, depends on both intrinsic material properties and surface processing. However, no detailed research has been done on the aerospace Ti-6Al-4V component tensile and double shear strength variation due to conducted surface processing on the component. Thus, the objective of this evaluation is to systematically evaluate the effect of various surface processings on the typical aerospace component, Ti-6Al-4V, including its fastener’s mechanical properties of both tensile and double shear strength. The three most common fastener surface processings were selected, including bare, aluminum organic coating, and dry film lubrication. Detailed statistical analyses, including Tukey’s HSD (honestly significant difference), were conducted to identify the relationship between the surface interactions and tested strength. Experimental results confirmed that fastener tested tensile and shear values dropped when surface processing was applied by up to 3.7%. This reduction was likely due to an elimination of localized seizing or galling from the additional lubrication instead of the intrinsic material degradation due to surface processing.