Compressive deformation and forging behavior of Ti14 alloy in semi-solid state

Deformation behavior and formability of Ti14, a new typical α + Ti2Cu alloy in the semi-solid state, were investigated by compressive tests in temperature range between 1223 and 1473 K and by forging tests between 1223 and 1373 K. Tensile tests of the forged alloys were also performed to study the effect of forging on mechanical properties. The results show that the maximum compressive stress was greatly dependent on the fraction solid, and that a transition in stress occurred at a solid fraction between 0.94 and 0.98 (corresponding to the temperature between 1323 and 1373 K). This transition was related to the decrease in amount of solid bridges between grains. Excellent formability and grain refinement due to dynamic recrystallization were achieved during the semi-solid forging. Furthermore, tensile tests showed a high ultimate tensile strength and yield strength after semi-solid forging at more than 1273 K, which was attributed to the grain refinement caused by the semi-solid forging. Ductility was also improved by changing the forging ratio. These results indicate that both good formability and tensile properties can be simultaneously attained by the compressive processing in the semi-solid state.