A new titanium alloy possessed close expansion coefficient to stainless steel

• The TiCuAlZr alloy possessed close expansion coefficient to stainless steel.
• The TiCuAlZr alloy exhibited strength and elongation of 1050 MPa and 8.5%.
• The expansion coefficient decreased with increased order degree in TiCuAlZr alloy.

The joining of titanium alloy to conventional structural steel has many industrial applications. However, it is difficult to join titanium alloys to steel due to great differences in thermal, physical, and chemical properties. Among these properties, the expansion coefficient is an important physical parameter. In this study, the expansion coefficient and mechanical properties of Ti–8Cu–5.7Al–3.8Zr (wt.%) alloy were studied. According to the experimental results, the eutectoid structure, which was composed of Ti2Cu and α phase, was observed in both air cooled and furnace cooled TiCuAlZr alloy after annealing at 800 °C. And the furnace cooled specimen revealed a more evident eutectoid structure. The results also showed that the difference of the average thermal expansion coefficients (−60 to 80 °C) between TiCuAlZr alloy and 9Cr18 martensitic stainless-steel were only 4%, which was beneficial to join titanium alloys to stainless steel. In addition, the air cooled specimen exhibited relatively good mechanical properties. The strength and the elongation were 1050 MPa and 8.5%, respectively.