A novel approach to enhance formability in Ti-6Al-4V alloy: Experimental investigations and microstructural analysis of pulsating tensile test

Abstract

Ti-6Al-4V alloy, widely utilized in aerospace, medical industries, and specialized applications, boasts exceptional properties. However, its limited formability poses challenges in manufacturing processes. The pulsating loading method emerges as a promising solution to enhance formability in such materials. This study delves into the impact of stress relaxation and loading-unloading tests on the formability of Ti‑6Al‑4V alloy, conducting tensile tests on sheets of two different thicknesses: 0.5 mm and 2.65 mm. Investigating parameters such as pulse starting strain, relaxation time, and strain increment in stress relaxation experiments, as well as unloading ratio and strain increment in loading-unloading experiments, enabled a comprehensive comparison of the two pulsating loading methods across different sheet thicknesses. Results indicate a notable increase in material formability, up to approximately 20 % for the 2.65 mm thickness and up to 50 % for the 0.5 mm thickness compared to monotonic loading. Stress relaxation time emerged as the most influential parameter for both thicknesses. Additionally, XRD analysis was employed to elucidate the microstructural reasons behind the observed formability enhancement, while SEM imaging provided insights into the fracture surface morphology. This systematic approach sheds light on the microstructural mechanisms underlying the effect of pulsating loading on material behavior.