Influence of Chemical Milling on the Mechanical and Microstructural Properties of Cased -Titanium Alloy

The presence of alpha casing in beta titanium can be detrimental to various forming applications and can be eliminated through chemical milling. The effect of the chemical milling process on the removal of alpha casing from the surface of beta titanium has been investigated extensively. Chemical milling is performed at different solution concentration ratios, and the specimens are characterized using Vickers hardness and surface roughness. The optimum results for chemical milling with a high material removal rate of 3.85 mm3/min are obtained with HF (10%) and HNO3 (10%). The effect of chemical milling on the mechanical strength of beta titanium is studied through tensile tests at room temperature and at increased temperature (200 degrees C). The maximum percentage of elongation obtained after chemical milling is around 24.4%, compared to 1.7% observed with the as-received specimen. Comprehensive analysis through optical microscopy, XRD, and EBSD confirmed the successful removal of the alpha casing from the beta-Ti alloy at both 0.7- and 0.5-mm chemical milling depths. The effectiveness of the chemical milling process is further investigated through fractography analysis of the tensile-tested specimens. Chemical milling with the specified solution proves to be an effective method for enhancing alpha casing removal and mechanical performance of beta-Ti alloys, making it a promising technique for various industrial applications.