Material characterization of ultrasonically consolidated laminated Ti-Al composites (UC-LMC)

Ultrasonic consolidation (UC) is an additive manufacturing process where thin and dissimilar metallic layers are bonded through the action of ultrasonic oscillation energy with low energy consumption. The surface oxide layer and the other contaminations between two surfaces are broken up with ultrasonic oscillation improving the bonding strength. This study aimed for investigating the mechanical behavior of laminated metal composite (LMC) blanks that consist of several layers of commercially pure titanium (CP-1) and pure aluminum (AA 1100) foils with different number of layers. The LMC blanks were ultrasonically consolidated on a thick aluminum substrate with three different numbers (1, 3, 5) of bi-layers. Each bi-layer consists of UC bonded one AA 1100 and one Ti foils. Both uniaxial (tensile) and biaxial (hydraulic bulge) tests were carried out under two strain rates and four different temperature levels to reveal the mechanical response of LMCs with different conditions. Increase in number of bi-layers resulted in higher overall strength of LMC's as titanium content in LMC is increased. Delamination of layers was observed for 1-bilayer LMC's at room temperature while curling was noted at higher temperature tests. The results obtained from tensile and hydraulic bulge tests were compared to observe significant differences in UTS values and elongation. The effect of temperature, loading condition, and strain rate on the material responses were discussed on the basis of test results. At low temperature, the strain and strength values of bulge samples were higher than the values of tensile samples. However, at high temperatures, lower strain and lower strength were obtained from bulge test. The maximum strain of 0.46 was obtained at 300°C test temperature for 5 bi-layer both parallel rolling direction sample in the all LMCs from tensile test.