2020 Volume 61 Issue 4 Pages 740-749
Ten types β-type titanium alloys for as-cast applications were proposed by using mainly ubiquitous elements in the area greatly differ from conventional alloys in compositions, in the diagram consisting of bond order (Bo) and d-orbital energy level (Md). The object was to develop β-type titanium alloys with ultimate tensile strength value of 1000 MPa and fracture strain value of 10% in as-cast condition without the post-treatments after cold crucible levitation melting, and their microstructures were controlled by adjusting its process parameters. The same microstructure and mechanical properties were also indicated on both as-cast and solution treated alloys, which mean the unnecessary of solution treatment in proposed alloys. Ti–5.2Cr–5.5Mn–2.2Fe–5.5Zr, Ti–11Cr–6Mn–4.5Zr–0.5Al and Ti–13Zr–6Mn–6Cr–5V alloys with a β mono phase achieved objective values of mechanical properties in as-cast condition, which lead to development of alternative materials to the conventional β-type titanium alloys, since they reduce energy consumption and 25% production costs by omitting complex post processing procedures. Moreover, the phase boundary between the mono β phase and dual β plus intermetallic compound phases were predicted for the first time in β-type titanium alloys, according to the ten proposed alloys in newly expanded compositional area of the Bot-Mdt diagram.