Microstructure and mechanical properties of a novel Ti-Al-Cr-Fe titanium alloy after solution treatment

The relationship between microstructure and mechanical properties of a novel Ti-3.0Al-3.7Cr-2.0Fe alloy were studied. The effects of cooling rates and solution temperature were considered. The analysis methods of optical microscope (OM), X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) were used. The results indicate that β and α phase in this alloy are obtained after solution treated at 1183 K on the cooling ways of air cooling and furnace cooling; and β and α″ martensite are observed after quenching in water. Besides, the volume of α phase is decreased with increasing solution temperature. In the present study, the ultimate strength 1065 MPa with 12.0% in elongation of the alloy is acquired under the heat treatment condition of 1183 K/30 min/AC, and the strength-ductility combination in this case is also the best. Under the heat treatment condition of 1183 K/30 min/WQ, the elasticity modulus of the alloy is only 91.3 GPa, as a result of the lower elasticity modulus of β phase.