Microstructure and mechanical properties of new metastable beta type titanium alloy

A new metastable beta type titanium alloy called TB-13 with the combination of excellent strength and ductility was developed successfully. In order to develop a perspective on this new alloy, the influence of several commonly used heat treatments on the microstructure and properties was studied. In solution-treated and quenched samples, a low-temperature aging at 480 degrees C results in the precipitation of finer alpha phase. The precipitation of coarser alpha phase plate at higher aging temperature (560 degrees C) leads to the increase of tensile ductility but reduction of strength. During low-temperature aging at 300 degrees C, quite homogeneous distribution of fine isothermal omega phase particles was found. The isothermal omega phase provides nucleation sites for alpha phase during two-step aging process and makes alpha phase extremely fine and disperse uniformly in beta matrix. Thus, TB-13 alloy is strengthened and its mechanical properties are improved.