| Title |
The Effect of Microstructure and Phase Transformation on Mechanical Properties for Ti3Al - Nb alloys |
| Authors |
최병학(B . H . Choe); 이용태(Y . T . Lee) |
| Abstract |
Various thermomechanical treatments were performed in order to optimize the ductility and strength of Ti₃Al-Nb alloys, called Alpha 2 and Super Alpha 2. The mechanical properties such as strength, elongation and hardness can be improved by the thermomechanical treatment. Especially Super Alpha 2 which has more β-stabilizing alloy elements than Alpha 2 exhibited gradually improved mechanical strength as the solution heat treatment temperatures are approached to the β-transus temperature. Further improvement of the hardness could be achived depending upon aging time and temperature. This is due to the phase transformation happened during thermomechanical treatment. Formation and quantity of the orthorhombic martensite phase is the most important factor on mechanical properties. The martensite is formed in the matrix after solution heat treatment and quenching. During aging the martensite transforms to stable secondary α₂+$quot;0$quot;+β/B2 phases which are distributed finely as lamellar type. These microstructural refinement. together with proper amount of primary α₂ Phase increases strength and hardness in Super Alpha 2. While in Alpha 2 the martensitic transformation is suppressed and strength improvement can not be achived. |