The effects of Nb content on microstructure and fracture behavior of near α titanium alloys

2015 ◽  
Vol 66 ◽  
pp. 267-273 ◽  
Author(s):  
Binguo Fu ◽  
Hongwei Wang ◽  
Chunming Zou ◽  
Zunjie Wei
Keyword(s):  
Titanium Alloys ◽  
Fracture Behavior ◽  
Nb Content

Comparative study of the oxide scale thermally grown on titanium alloys by ion beam analysis techniques and scanning electron microscopy

2008 ◽  
Vol 23 (8) ◽  
pp. 2245-2253 ◽  
Author(s):  
A. Gutiérrez ◽  
F. Pászti ◽  
A. Climent-Font ◽  
J.A. Jiménez ◽  
M.F. López
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Titanium Alloys ◽  
Oxide Scale ◽  
Ion Beam ◽  
Elastic Recoil ◽  
Detection Analysis ◽  
Nb Content ◽  
Scanning Electron

In the present work, the oxide layers developed at elevated temperature on three vanadium-free titanium alloys, of interest as implant biomaterials, were studied by Rutherford backscattering spectroscopy, elastic recoil detection analysis, and scanning electron microscopy. The chemical composition of the alloys investigated, in wt%, was Ti–7Nb–6Al, Ti–13Nb–13Zr, and Ti–15Zr–4Nb. Upon oxidation in air at 750 °C, an oxide scale forms, with a chemical composition, morphology, and thickness that depend on the alloy composition and the oxidation time. After equal exposure time, the Ti–7Nb–6Al alloy exhibited the thinnest oxide layer due to the formation of an Al2O3-rich layer. The oxide scale of the two TiNbZr alloys is mainly composed of Ti oxides, with small amounts of Nb and Zr dissolved. For both TiNbZr alloys, the role of the Nb-content on the mechanism of the oxide formation is discussed.

scholarly journals Interfacial Reactions and Fracture Behavior of Ti Alloy-Ag28Cu Brazing Joints: Influence of Titanium Alloy Composition

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 830 ◽  
Author(s):  
Joachim Gussone ◽  
Galina Kasperovich ◽  
Jan Haubrich ◽  
Guillermo Requena
Keyword(s):  
Titanium Alloys ◽  
Fracture Behavior ◽  
Titanium Substrate ◽  
Tensile Tests ◽  
Coarse Grained ◽  
X Ray ◽  
Fine Grained ◽  
Β Phase ◽  
Brazed Joints ◽  
Crack Paths

Brazing of titanium provides a joining technique suitable for the fabrication of highly-loaded aerospace components, but it still poses numerous challenges, such as the formation of brittle intermetallic interphases. This study of the interphase formation in brazed joints consisting of different titanium alloys (Ti-CP2, Ti-CP4, Ti-6Al-4V, Ti-6Al-2Mo-4Zr-2Sn) and Ag28Cu shows that complex reactions lead to the formation of various intermetallic phases including a Ti2Cu-TiCu boundary zone. The compositions of the titanium alloys influenced the particular microstructures, which have been characterized with various methods including synchrotron X-ray microtomography. Tensile tests evidence high ultimate tensile strengths that are, importantly, not directly limited by the strength of the brazing alloy. The strength of the Ti2Cu-TiCu phase boundary is significantly increased by the alloying elements in Ti-6Al-4V and Ti-6Al-2Mo-4Zr-2Sn and the crack paths change from boundary failure to transcrystalline fracture through TiCu as well as Ag-rich regions. Cu diffusion into the titanium substrate, leading to a coarse grained β-phase that transforms eutectoidally into a lamellar α-Ti + Ti2Cu structure during cooling, occurred in all systems except Ti-6Al-2Mo-4Zr-2Sn where Mo stabilized a fine grained microstructure and enabled the formation of a columnar TiCu structure.

The effect of impurity on the deformation and fracture behavior in vanadium-20 wt.% titanium alloys

1996 ◽  
Vol 34 (2) ◽  
pp. 317-323 ◽  
Author(s):  
D.Y. Lyu ◽  
T.E. Bloomer ◽  
Ö. Ünal ◽  
J. Kameda
Keyword(s):  
Titanium Alloys ◽  
Fracture Behavior ◽  
Deformation And Fracture

Chip Fracture Behavior in the High Speed Machining of Titanium Alloys

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Xueping Zhang ◽  
Rajiv Shivpuri ◽  
Anil K. Srivastava
Keyword(s):  
Titanium Alloy ◽  
Phase Transformation ◽  
Titanium Alloys ◽  
High Speed ◽  
Fracture Behavior ◽  
High Strain ◽  
Failure Strain ◽  
Stress Triaxiality ◽  
High Speed Machining ◽  
Strain Intensity

Machining of titanium alloy is a severe fracture procedure associated with localized adiabatic shearing process. Chip segmentation of titanium alloy is usually characterized with adiabatic shear band (ASB) and localized microfracture evolution process. ASB has been recognized as the precursor of fracture locus due to its sealed high strain intensity. Besides strain intensity, stress triaxiality (pressure-stress states) has also been identified as a significant factor to control fracture process through altering critical loading capacity and critical failure strain. The effect of stress triaxiality on failure strain was traditionally assessed by dynamic split Hopkinson pressure bar (SHPB), quasi-static tests of tension, compression, torsion, and shear for finite element (FE) analysis. However, the stress triaxiality magnitudes introduced by these experiments were much lower than those generated from the high speed machining operation due to the fact that ASBs in chip segmentation are usually involved in much higher strain, high strain rate, high stress, and high temperature associated with phase transformation. However, this aspect of fracture evolution related with stress triaxiality and phase transformation is not well understood in literature. This paper attempts to demonstrate the roles of stress triaxiality and phase transformation in chip segmentation especially in the high speed machining of titanium alloy in FE framework. Johnson–Cook (JC) failure model is calibrated by addressing the characteristics of stress triaxiality and phase transformation associated with high speed machining. This research confirms that the selection of failure criterion parameters incorporated the effects of stress triaxiality and the alpha–beta phase transformation is indispensible to successfully predict fracture behavior during chip segmentation process in the high speed machining of titanium alloys.

scholarly journals Superplastic Grade Titanium Alloy: Comparative Evaluation of Mechanical Properties, Microstructure, and Fracture Behavior

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
K. V. Sudhakar ◽  
Ethan Wood
Keyword(s):  
Heat Treatment ◽  
Titanium Alloys ◽  
Comparative Evaluation ◽  
Fracture Behavior ◽  
Test System ◽  
The Other ◽  
Static Fracture ◽  
Strength And Ductility ◽  
Biomedical Fields ◽  
Made In

In this investigation, static fracture, microstructure, and the mechanical behavior of SP-700 alloy (a superplastic grade) were evaluated and compared with two other titanium alloys. The comparisons were made in terms of suitably designed heat treatment cycles. The heat treatment cycles included annealing and a combination of solutionizing and aging treatments for all three alloys. Tensile properties were determined using MTS Landmark Servohydraulic Test System. Tensile tested samples’ fracture surfaces were investigated with LEO-VP SEM instrument. Ti-15-3-3-3 alloy exhibited relatively a higher combination of strength and ductility in comparison to the other two alloys. All three types of titanium alloys demonstrated a very good level of tensile strength and ductility suitable for applications in military and biomedical fields.

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