The constitutive behavior of Ti-5Al-3V-2Cr-2Fe under high-velocity impact: Experimental, modeling, and validation

The compressive and tensile stress-strain relationship and fracture behavior of a new low-cost titanium alloy Ti-5Al-3V-2Cr-2Fe (Ti-5322) at 286-573 K, a strain rate of 0.0001-4300 s(-1) and a stress triaxiality of 0.43-1.6 were studied. Based on the experimental data, the flow and fracture behavior of Ti-5322 was established based on the Johnson-Cook (J-C) equation. Ballistic impact tests were used to study the ballistic performance of a 7-mm-thick Ti-5322 target and the accuracy of the constitutive model was verified from the ballistic test results. The experimental results showed that the yield strength and strain rate of the Ti-5322 were related logarithmically. As the strain rate increased, the rate-strengthening behavior of the material weakened gradually. The material had an obvious thermal-softening behavior and the yield strength decreased linearly with an increase in deformation temperature. The stress triaxiality and strain rate had a significant effect on the fracture behavior of Ti-5322. The material fracture strain decreased with the stress triaxiality and an increase in strain rate. The J-C constitutive model was a good predictor for the ultimate penetration velocity of the Ti-5322 target and the velocity decay of fragments during penetration. The ballistic limit velocity of the 10-mm-diameter tungsten-alloy ball to the 7-mm-thick Ti-5322 target at 0 degrees and 30 degrees was 416.0 m/s and 484.8 m/s, respectively. (C) 2019 Elsevier B.V. All rights reserved.