Structure and Properties of Ti/TiB Metal-Matrix Composite after Isothermal Multiaxial Forging

Microstructure and mechanical properties of a Ti/TiB metal-matrix composites after multiaxial forging at 850 degrees C to the true strain epsilon = 5.2 were studied. The composite with 17 vol.% of TiB was produced via spark plasma sintering at 1000 degrees C. Mechanical behavior in terms of aggregated sigma-Sigma epsilon curves during the multiaxial forging demonstrated a pronounced softening following by a steady-like flow stage. The length of TiB whiskers considerably decreased after the first step of the multiaxial forging and then changed insignificantly. The microstructure after the MAF consisted of dislocation-free Ti matrix areas of approximate to 1 mu m in diameter and areas with high density of TiB whiskers and high dislocation density. The forging resulted in a considerable increase in ductility of the Ti/TiB metal-matrix composites at room and elevated temperatures without loss in strength.