The Analysis of Changes in the Crystal Structure of Near-Beta Titanium Alloy in the Solution-Treated and Aged Conditions after Static Tensile Testing

Abstract

Titanium alloys are characterized by insufficient ductility. One of the parameters affecting their ductility is their crystal structure and texture. The present study characterizes the changes in the crystallographic texture of the Ti-3Al-8V-6Cr-4Zr-4Mo alloy in solution-treated and aged conditions on the basis of texture intensity indices and pole figures. Analysis of crystal structure changes was performed before and after tensile testing. The investigated alloy in the solution-treated condition showed a single-phase β-solution structure with a body-centered cubic (BCC) crystal structure. The process of β phase aging affected the result of the tensile test, affecting the parameters of the texture of the β phase. The analysis of the texture intensity indices for each set of planes (hkl) related to the intensity for the plane (110) indicated that the highest texture intensity occurs for β titanium alloy aged at 550 °C both before and after tensile test. After plastic deformation, the largest difference with respect to the benchmark value was observed for the (220) and (310) planes. The least amount of texture intensity occurred after aging at 450 °C. The most varied values of diffraction peak intensity in relation to the benchmark were obtained for the alloy aged at 450 °C for the (310), and (200) and (211) planes, indicating the dominance of the (211) orientation, where an elongation of 10.4% was achieved. For the highest elongation of 14.2%, achieved for the sample solution-treated at 550 °C, the diffraction peak intensities were intermediate with the dominance of peaks from the planes (200) and (310).

Keywords

• near-β titanium alloy
• supersaturation
• aging
• tensile test
• crystallographic texture