Effects of Trace Boron Addition and Different Arc Types on Microstructure and Mechanical Properties of TC11/TC17 Dual Alloy Fabricated by Wire Arc Additive Manufacturing

Wire arc additive manufacturing (WAAM) provides an efficient and low-cost potential for manufacturing TC11/TC17 dual titanium alloy. In this work, six deposition samples were fabricated for the test of microstructure and mechanical properties by the combination of trace boron addition and different arc types (direct current (DC), high frequency pulsed current (HC), low frequency pulsed current (LC)). Results show that the epitaxial growth beta columnar grains were formed except for the combination of low frequency pulsed current and trace boron addition (LCB). A special microstructure of coarser alpha phases surrounding thin alpha phases was formed by the effect of LC arc or trace boron addition. Some TiB particles exhibited a specific orientation relationship with surrounding alpha phases, but not all: (0001)alpha||(001)TiB and alpha||[010]TiB. About mechanical properties, the elongation decreased with trace boron addition, and comprehensive mechanical properties of LC method was better than that of DC or HC methods whether it contained trace boron or not, with tensile strength of 1057 MPa and elongation of 14.4% in the longitudinal direction. Meanwhile, the strength of LCB group is highest than that of other groups, which is caused by the refined beta grains and the uniform distribution of TiB particles.

Automated summary

Wire arc additive manufacturing (WAAM) is an efficient and low-cost method for manufacturing titanium alloys. In this study, deposition samples were fabricated with trace boron addition and different arc types, and their microstructure and mechanical properties were tested. The results show that the LC method has the best comprehensive mechanical properties, and the addition of trace boron decreases the elongation.