| Titanium-Boron alloys have gained significant interest in the last few years, especially in the aerospace community where emphasis has been on developing more structurally efficient materials. The new class of alloys achieves higher strength and stiffness, up to 60% in some cases, than most conventional titanium alloys utilized today. An in-situ reaction precipitates the important needle-like TiB reinforcement phase, which is responsible for the tremendous increase in properties. Strengths as high as 1700MPa and stiffness near 200 GPa have been realized in laboratory mechanical testing. The compatibility of the TiB phase with the surrounding alloy, and the low solid solubility provide a stable material system, yet much is not known in regards to the thermal stability of the TiB phase. As it is well understood that heat treatment conditioning of conventional Ti alloys can produce a wide array of microstructural and property results, therefore, it is expected that Ti-B alloys may respond to thermal exposure in similar fashion. Two alloys, Ti-6Al-4V-1.0B and Ti-6Al-4V-1.71B, produced via a prealloyed powder metallurgy approach and subsequent extrusion, were selected for this research. The goal of this research was two-fold, (i) to analyze and quantify the thermal stability of the in situ TiB phase present in a pre-selected Ti-B alloy, (ii) to study the microstructural-mechanical property response of the two pre-selected Ti-B alloys via exposure to predetermined heat treatments and compare to conventional Ti-6Al-4V. |
