Influence of Electric Heating Process on Black Spot Structure Evolution and Tensile Properties of Ti-55511 Alloy

The solid soluted Ti-55511 alloy was treated by electric heating for different holding times (10-60 s) at 905 ℃, and the evolution of black spot structure and tensile properties of the alloy were studied. The results show that the β phase of black spot structure in the alloy in solid solution state had a typical Goss and Cube texture orientation. With the electric heating time increasing from 10 s to 40 s, β grains recrystallized and the black spot structure content decreased. When electric heating for 60 s, the recrystallization grain grew to average grain size of 27.3 μm and the black spot structure area fraction decreased to 2.1%. Comparing with those of the solid soluted alloy, the tensile strength of the alloy after electric heating decreased while the elongation after fracture increased. With increasing electric heating time, the tensile strength of the electric heating reated alloy kept unchanged, and the elongation after fracture increased first and then decreased, reaching the maxium value of 20.8% when electric heating for 40 s. The fracture of the alloy after electric heating for different times showed the composite morphology of dimples and quasi-cleavage fracture.