High damping NiTi/Ti3Sn in situ composite with transformation-mediated plasticity

• Transformation induced plasticity is introduced to improve the plasticity of Ti3Sn.
• The composite exhibits a high damping capacity and excellent mechanical properties.
• Synchrotron X-ray diffraction measurements revealed the phase transformation behavior.

The concept of transformation-induced plasticity effect is introduced in this work to improve the plasticity of brittle intermetallic compound Ti3Sn, which is a potent high damping material. This concept is achieved in an in situ NiTi/Ti3Sn composite. The composite is composed of primary Ti3Sn phase and (NiTi + Ti3Sn) eutectic structure formed via hypereutectic solidification. The composite exhibits a high damping capacity of 0.075 (indexed by tan δ), a high ultimate compressive strength of 1350 MPa, and a large plasticity of 27.5%. In situ synchrotron high-energy X-ray diffraction measurements revealed clear evidence of the stress-induced martensitic transformation (B2 → B19′) of the NiTi component during deformation. The strength of the composite mainly stems from the Ti3Sn, whereas the NiTi component is responsible for the excellent plasticity of the composite.