Preparation of low cost TiZrAlFe alloy with ultra-high strength and favorable ductility

Cost reducing has always been a very important future development for Ti alloys. A new series of low cost TiZrAlFe alloys with ultra-high strength and favorable ductility are developed in this work. The microstructure and mechanical properties of the new series of low cost TiZr based alloys with Fe content from 0.5 to 2.0 wt% are investigated. As Fe content increases from 0.5 to 2.0 wt%, the β to α phase transition temperature decreases from 836 to 768 °C, and the phase constitution of the examined alloys changes from α′+β to αʺ+β and finally whole β phase. That acicular α′ martensite precipitating out of β matrix is the microstructural feature of the developed low cost alloy with Fe content of 0.5 wt%. As the Fe content increases to 1.0 wt%, the microstructural characteristic is some ultra-fine lenticular αʺ martensites with tens nanometers thickness enchased in β matrix. As the Fe content further increases to 1.5 wt%, the β grains generate recrystallization. Microstructural features of β grains further recrystallization and growth exhibit in the examined alloy with Fe content of 2.0 wt%. Tensile results show that the new series of low cost alloys have ultra-high strength and favorable ductility. The strength of the examined alloys changes from 1495 to 1212 MPa as the increasing of Fe content from 0.5 to 2.0 wt%. Meanwhile the total elongation ranges from 8.3% to 12.4%. The strengthening mechanism of the developed low cost TiZr based alloys is also discussed. The current finding not only presents an excellent alloy with superior combination of strength and ductility but promotes the development and application of low cost Ti alloys.