Preparing and Etching Titanium to Document Surface Effects

Abstract

Abstract This paper is a follow-up and update of the article “Titanium and Its Alloys” in Volume 9 of the ASM Handbook, Metallography and Microstructures [1]. Because of its inherent characteristics, titanium is one of the more difficult metals to prepare for metallographic examination, as illustrated below. The challenge is to understand and minimize metallographic preparation artifacts through an understanding of their cause. They will be introduced if the wrong preparation steps and/or etching techniques are applied. For example, if one used the metallographic preparation process for a body centered cubic tempered martensitic steel, etching of Ti and its alloys would not reveal the true structure. This article covers the effect of etchant selection and etching time, the effect of remnant mechanical deformation and cold work produced during specimen preparation, the influence of interstitial contamination and enrichment on the microstructure, and the effect of these problems on heat affected zones.