Development of α - β type titanium alloy Ti-4.5Al-2.5Cr-1.2Fe-0.1C-0.3Cu-0.3Ni having good forgeability and machinability

Abstract

Development of a titanium alloy having excellent hot forgeability and machinability while having the same properties as Ti-64 alloy is effective in reducing the total cost of titanium parts. To develop a new alpha-beta type titanium alloy which has good hot forgeability, machinability and tensile properties equivalent to those of Ti-64 alloy at room temperature, Ti-4.5Al-2.5Cr-1.2Fe-0.1C-nCu-nNi (n=0 to 2) were prepared and evaluated. The new alloy showed tensile properties equivalent to that of Ti-64 alloy at room temperature. On the other hand, the hot deformation stress of new alloy was about 30% lower than that of Ti-64 alloy, and the excellent deformability was confirmed. The addition of Cu and Ni to Ti-4.5Al-2.5Cr-1.2Fe-0.1C alloy suppressed the amount of wear of tool and improved the machinability. Tool life of new alloy machining is extended by about 1.5 times compared to that of Ti-64 alloy. Addition of Cu and Ni is considered to reduce the reactivity between tool and workpiece and improve machinability.

Keywords

• alpha-beta type titanium alloy (α-β type titanium alloy)
• hot forging
• machining