Influence of UFG structure formation on mechanical and fatigue properties in Ti-6Al-7Nb alloy

6th International Conference on Nanomaterials by Severe Plastic Deformation

材料科学;化学

Polyakova, V.V.^1 ; Anumalasetty, V.N.^2 ; Semenova, I.P.^1 ; Valiev, R.Z.^1,3

Ufa State Aviation Technical University, K. Marx Street 12, 450 000, Ufa, Russia^1

Carpenter Technology Corporation, RandD Bldg.68, POBox: 14662, Reading, PA, 19612-4662, United States^2

Laboratory for Mechanics of Bulk Nanostructured Materials, Saint Petersburg State University, Universitetsky pr. 28, Peterhof, 198504, Saint Petersburg, Russia^3

关键词: Coarse grained alloys;    Cyclic fatigue tests;    Fatigue endurance limit;    Fatigue properties;    Fatigue striations;    Thermo-mechanical processing;    UFG microstructure;    Ultrafine-grained Ti;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/63/1/012162/pdf
DOI  :  10.1088/1757-899X/63/1/012162

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Ultrafine-grained (UFG) Ti alloys have potential applications in osteosynthesis and orthopedics due to high bio-compatibility and increased weight-to- strength ratio. In current study, Ti6Al7Nb ELI alloy is processed through equal channel angular pressing-conform (ECAP-Conform) and subsequent thermomechanical processing to generate a UFG microstructure. The fatigue properties of UFG alloys are compared to coarse grained (CG) alloys. Our study demonstrates that the UFG alloys with an average grain size of ∼180 nm showed 35% enhancement of fatigue endurance limit as compared to coarse-grained alloys. On the fracture surfaces of the UFG and CG samples fatigue striations and dimpled relief were observed. However, the fracture surface of the UFG sample looks smoother; fewer amounts of secondary micro-cracks and more ductile rupture were also observed, which testifies to the good crack resistance in the UFG alloy after high-cyclic fatigue tests.