Carbon in Commercially Pure Titanium

Abstract

In a way so far unmatched in any single study, this paper presents the complex characteristics of commercially pure titanium (CP-Ti) containing 0.2 wt.% carbon, which is significantly above the carbon level in commonly used titanium alloys, while at the same time being the maximum permitted content in light of the recommendations in force. It has been demonstrated that the addition of carbon in CP-Ti can have many positive impacts. The investigated Ti-0.2C alloy was produced in a cold-copper crucible induction vacuum furnace and processed into a 12 mm diameter bar by hot rolling. The structure and properties of the Ti-0.2C alloy were compared to those of an CP-Ti Grade 1 produced and processed under the same technical conditions. The addition of 0.2 wt.% carbon to CP-Ti has been found to change the course of the crystallization process, the course and temperatures of phase transformations, and the values of lattice parameters; reduce susceptibility to grain growth; and create the possibility for additional hardening during solution treatment and aging. At the same time, it results in an assumed improvement in properties by increasing the tensile strength and yield strength, hardness, creep and oxidation resistance, and abrasive wear. It has a negative effect but is still within the acceptable range on impact strength and susceptibility to hot and cold deformation.