Influence of Nb on Microstructure and Mechanical Properties of Ti-Sn Ultrafine Eutectic Alloy

Abstract

In this study, A series of the high strength (T82Sn18)(100-x)Nb-x (x=0, 1, 3, 5, and 9 at%) ultrafine eutectic alloys with large plasticity are developed by suction casting method. The Ti18Sn18 binary eutectic alloy consists of a mixture of a hcp Ti3Sn and a alpha-Ti phases having the plate-like lamellar type duplex structure with micro scaled eutectic colony. From the (T82Sn18)(97)Nb-3, the alloy display structural heterogeneous distribution of ultrafines-caled phases composed of beta-Ti(Nb) solid solution surrounded by alternating plate-like shaped Ti3Sn and alpha-Ti phases. With increasing Nb content, the volume fraction of beta-Ti is continuously increased, which induced improving mechanical properties both strength and plasticity. Especially, (Ti82Sn18)(91)Nb-9 alloy has the outstanding combination of the high strength (sigma(y)approximate to 1.1 GPa) and large plasticity (epsilon(p)approximate to 36%) at room temperature.