Deformation Characteristics and Mechanical Properties of Ti/Al Bimetallic Composite Materials Fabricated by Wire Plus Arc Additive Manufacturing

Abstract

We focused on Ti/Al composite materials fabricated by wire and arc addictive manufacturing, and the microstructure and interface characteristics of them before and after hot compression deformation were compared. After compression deformation, all α structures of titanium were compacted with the emergence of Widmanstatten structures. Coarsened colonies α of titanium were elongated and waved along the original growth direction, resulting in anisotropy of grains. Pores and Ti/Al intermetallic compounds of aluminum are significantly decreased after hot compression. Meanwhile, a good bonding interface between titanium and aluminum is obtained after hot compression, and the element diffusion is more intense. In addition, the mechanical properties and fracture behaviors of Ti/Al composite material with different clad ratio that is defined as the ratio of the thickness of titanium to that of the Ti/Al composite material are investigated by uniaxial tensile test. The experimental results show that the ultimate tensile strength of Ti/Al composite material is between that of single deposited titanium and aluminum, while the elongation of Ti/Al composite material with low clad ratio is lower than that of single aluminum due to the metallurgical reaction. As the clad ratio increases, the two component layers are harder to separate during deformation, which is resulted from the decrease of the inward contraction stress of three-dimensional stress caused by necking of aluminum. This work may promote the engineering application of Ti/Al bimetallic structures.

Keywords

wire plus arc additive manufacturing / aluminium alloy / titanium alloy / bimetallic composite materials / deformation / mechanical properties