Room Temperature Mechanical Properties and Formability of β and α plus β Titanium Alloy Sheets

In the present study, the room temperature mechanical properties and formability of metastable beta-Titanium (beta-21S) and Ti-6Al-4V (alpha + beta) alloys in sheet form are evaluated and compared. The alloys are subjected to various deformation modes, such as biaxial stretching, stretch flanging and deep drawing. Formability was characterized in terms of forming limit curve (FLC), limiting dome height (LDH), hole expansion ratio (HER) and limiting draw ratio (LDR). Uniaxial tensile tests were conducted to determine the mechanical properties, anisotropic parameters and flow curves. beta-21S exhibited flow softening with similar strength, higher ductility and lower anisotropy than Ti-6Al-4V. Forming limit curves (FLCs) of both alloys were determined by performing tests in different strain paths using the simplified Hecker's method. The FLCs showed that limit strains of beta-21S are marginally higher than Ti-6Al-4V. In addition, the LDH, HER and LDR values of beta-21S are found to be higher than that of Ti-6Al-4V. Thus, the findings indicate better overall formability of metastable beta-21S alloy making it more suitable than Ti-6Al-4V for room temperature forming applications.