Effect of hot forging on microstructure and tensile properties of Ti–TiB based composites produced by casting

Abstract

Microstructure and mechanical behavior of near eutectic Ti–1.5 wt% B and hypereutectic Ti–2B wt% B composite materials obtained by casting have been investigated. Commercially pure titanium was used as a matrix material. Homogeneously distributed TiB whiskers were revealed in the as-cast composite materials. Multiple isothermal 2-D forging of the composites was carried out in the temperature range of the beta phase field. The hot forging led to effective alignment of boride whiskers while retaining a high aspect ratio. Tensile mechanical tests in as-cast and forged conditions were carried out at room and elevated temperatures. The composites demonstrated much higher strength in comparison with the matrix material without drastic ductility reduction. The effect of boride orientation and morphology on the tensile properties of the composite materials is discussed.