Additive manufacturing of titanium alloys with enhanced strength and uniform ductility via multi-element alloying

Abstract

The application of commercially pure titanium (CP–Ti) has long been limited by its insufficient strength and plastic instability. However, strength enhancement typically comes at the expense of ductility since the two important mechanical properties are often mutually exclusive. In the present work, multi-element Fe–Cr–Ni–Mo in the form of 316L steel was added into CP-Ti by additive manufacturing (AM), so as to realize the simultaneous enhancement of strength and uniform ductility. The localized homogenization of CP-Ti and 316L alloy melts during laser melting deposition produced the microstructure comprised of basket-weave ɑ laths, discontinuous ɑGB, and retained β phases, which endowed Ti-1.35Fe-0.36Cr-0.24Ni-0.05Mo alloy with related higher ultimate tensile strength (635 MPa) and larger uniform ductility (12%). This approach could provide guidance for designing high-performance metal materials starting with elements powder through additive manufacturing.

Keywords

• Additive manufacturing
• In-situ alloying
• Titanium alloys
• Uniform ductility