Effects of different microstructure types on the strength and plasticity of TC21 alloy

The room temperature tensile properties of TC21 titanium alloy with three different microstructures were tested after solution treatment followed by different cooling. Optical microscope and scanning electron microscopy were used to observe the microstructures. Relationships between the microstructure and the tensile properties were analyzed. The result shows that the best match between the strength and the plasticity (the yield strength>1000 MPa) can be achieved when the heat treatment processes and microstructures are as following: 920°C/1 h, FC+550°C/4 h equiaxed microstructure, 920°C/1 h, FC+550°C/4 h basket weave microstructure, and 960°C/0.5 h, FC+550°C/4 h lamellar microstructure. The better comprehensive properties could be obtained by controlling the α phase volume fraction and morphology, α phase colony size and α lamellae thickness in the colony.