Influence of testing orientation on mechanical properties of Ti45Nb deformed by high pressure torsion

Year: 
2016
Month: 
10
Day: 
19
Pages: 
40-46
DOI: 
10.1016/j.matdes.2016.10.035
Type: 
Journal Articles
Journal: 
Materials & Design
Volume: 
114
Abstract: 

Ti45Nb is a promising choice as an implant material due to its low Young's modulus and its good biocompatibility, however the material's strength is relatively low in the conventionally coarse-grained state. Recently, severe plastic deformation was suggested to improve the mechanical properties of such materials. In this study the influence of the testing direction on the mechanical properties including strength, ductility and fracture toughness is investigated using relatively large HPT samples with a diameter of ~ 30 mm and a thickness of ~ 7 mm. It is shown that especially the strength and fracture toughness develop a pronounced orientation dependence. With respect to the testing direction, the strength increased from ~ 400 MPa in the coarse-grained state to around 950 to 1050 MPa after deformation and the fracture toughness remains quite high with values between 75 and 110 MPa m1/2. Hence, the deformed Ti45Nb alloy represents an alternative to other Ti-alloys recently used as implant materials with the major advantage of having a low Young's modulus combined with high strength and fracture toughness.