Correlation Between Tensile Strength and Hardness of Electron Beam Welded TC4-DT Joints

Correlation between tensile strength and hardness for damage-tolerant Ti-6Al-4V (TC4-DT) alloy and its electron beam welded joints was investigated. Yield strength (YS), ultimate tensile strength (UTS) and strain hardening coefficient of base metal and weld metal were obtained using uniaxial tensile tests. Microhardness of the base metal, heat affected zone, and weld metal was measured. Then, the linear correlations among the yield strength, tensile strength, and hardness were proposed. Moreover, correlation between strain hardening coefficient and the ratio of YS to UTS (YS/UTS) was established. The results indicate that microhardness can be used to predict the YS and UTS of the TC4-DT welded joint successfully. In addition, the strain hardening coefficient can be predicted by the YS/UTS. The prediction of strength and strain hardening coefficient is in agreement with the experiments. The correlations are applicable and valuable for the strength prediction of narrow welded fusion zone and heat affected zone based on the microhardness measurement.