scholarly journals High temperature oxidation and mechanical behavior of β21s and Ti6242S Ti-based alloys

2020 ◽  
Vol 321 ◽  
pp. 04011
Author(s):  
Aurelie Vande Put ◽  
Carole Thouron ◽  
Philippe Emile ◽  
Raphaëlle Peraldi ◽  
Benjamin Dod ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Room Temperature ◽  
Tensile Tests ◽  
Lower Amount ◽  
Aircraft Industry ◽  
Micro Hardness ◽  
Temperature Oxidation ◽  
Specific Strength ◽  
High Specific Strength

Aircraft industry always looks for higher in-service temperatures and lighter structures. With a high specific strength, Ti-based alloys are good candidates for such applications. However, when exposed to oxidizing environments at high temperatures, they undergo large oxygen dissolution while forming an oxide scale, which can greatly affect their mechanical properties. Then, evaluating the oxidation resistance and mechanical behavior of such alloys is essential. In this aim, long term oxidation tests were performed under laboratory air between 500 °C and 625 °C on two Ti-based alloys: β21s, exhibiting a fully β microstructure supposed to dissolve lower amount of oxygen and nitrogen, and Ti6242S, with an α/β microstructure. The oxidized samples were characterized using XRD, Raman spectroscopy, SEM-EDS and micro-durometer. As for the mechanical behavior, tensile tests were performed at room temperature on not aged and on oxidized samples. While larger mass variations were obtained at 500 and 560 °C and up to 997 h at 625 °C for β21s, its mass variations became lower than those of Ti6242S for longer durations at 625 °C. Nevertheless, β21s exhibited thicker micro-hardness affected depths and underwent larger mechanical property modifications compared to Ti6242S.

Strengthening Evaluation in a Composite Mg-RE Alloy Using TEM

2011 ◽  
Vol 678 ◽  
pp. 75-84 ◽  
Author(s):  
Marcello Cabibbo
Keyword(s):  
Electron Microscopy ◽  
Metal Matrix ◽  
Room Temperature ◽  
Strengthening Mechanism ◽  
Composite Alloy ◽  
Specific Strength ◽  
High Specific Strength ◽  
Transmission Electron ◽  
Sic Ceramic

Magnesium alloys containing rare earth elements are known to have high specific strength and corrosion resistance. The addition of SiC ceramic particles makes the metal matrix composite stronger with better wear and creep resistance and a still good machinability. The role of the reinforcement particles to the enhanced strength can be quantitatively evaluated using transmission electron microscopy (TEM). This paper presents a quantitative strengthening evaluation in a SiC Mg-RE composite alloy. The different contributions were determined by TEM inspections. The microstructure strengthening mechanism was studied after room temperature compression specimens. The way of combining the different contributions and the comparison to the measured yield stress, is also discussed and justified.

scholarly journals The effect of loading frequency on the cyclic mechanical behavior of polyethylene

2015 ◽  
Vol 18 (4) ◽  
pp. 162-169
Author(s):  
Thao Song Thanh Nguyen ◽  
Nhung Thi Tuyet Le
Keyword(s):  
Experimental Investigation ◽  
Mechanical Behavior ◽  
Hysteresis Loop ◽  
Room Temperature ◽  
Tensile Tests ◽  
Loading Frequency ◽  
Ratcheting Strain ◽  
Accumulated Strain ◽  
Long Time ◽  
Kinetics Of

An experimental investigation into ratcheting strain and stress-strain hysteresis loop in stress-controlled cyclic tensile tests at room temperature was performed to determine the effect of loading frequency on the cyclic mechanical behavior of highdensity polyethylene (HDPE). It was found that frequencies ranging from 0.01 Hz up to 1 Hz mostly affects the accumulated strain over related time scales (i.e that of the cycle itself) and not over long time scale (i.e. during the full test). In addition, the higher the frequency is, the more closed and vertical the loops are. Furthermore, the frequency affects only on the kinetics of stabilization of ratcheting strain but not on one of hysteresis loop.

The Thermal-Mechanical Behavior of Selected Si3N4 and SiC Ceramics

1996 ◽  
Author(s):  
Norman L. Hecht ◽  
Hongsang Rho ◽  
Nora R. Osborne ◽  
Dale E. McCullum ◽  
Steven M. Goodrich
Keyword(s):  
Mechanical Behavior ◽  
Room Temperature ◽  
Failure Mechanisms ◽  
Property Values ◽  
Heat Engine ◽  
Cyclic Fatigue ◽  
Sic Ceramics ◽  
Environment Temperature ◽  
Fatigue And Fracture

This paper presents the results of a long term program initiated in December of 1984 to investigate the effects of environment (temperature, atmosphere, and stress) on the mechanical behavior of eight Si3N4 and three SiC ceramics being considered for heat engine applications. Microstructure, chemistry, and physical properties were determined. The mechanical behavior of these materials was investigated from room temperature to 1400°C by employing tests for flexural and tensile strength, dynamic, static and cyclic fatigue, and fracture toughness. The results obtained from these evaluations showed that the thermal mechanical behavior was quite varied, depending on the composition and processing methods employed. Batch to batch differences were also found to cause variances in the property values measured. Insights gained from this work about the failure mechanisms and potential service life are also discussed.

scholarly journals Mechanical and microstructural properties of EN AW-6060 aluminum alloy joints produced by friction stir welding

2015 ◽  
Vol 63 (2) ◽  
pp. 475-478
Author(s):  
I. Küçükrendeci
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Room Temperature ◽  
Weld Zone ◽  
Tensile Tests ◽  
Optical Observations ◽  
Microstructural Properties ◽  
Micro Hardness ◽  
Friction Stir ◽  
Mechanical And Microstructural Properties

Abstract In the study, the mechanical and microstructural properties of friction stir welded EN AW-6060 Aluminum Alloy plates were investigated. The friction stir welding (FSW) was conducted at tool rotational speeds of 900, 1250, and 1500 rpm and at welding speeds of 100, 150 and 180 mm/min. The effect of the tool rotational and welding speeds such properties was studied. The mechanical properties of the joints were evaluated by means of micro-hardness (HV) and tensile tests at room temperature. The tensile properties of the friction stir welded tensile specimens depend significantly on both the tool rotational and welding speeds. The microstructural evolution of the weld zone was analysed by optical observations of the weld zones

Effect of Intercritical Annealing Time on Microstructure and Mechanical Behavior of Advanced Medium Mn Steels

2012 ◽  
Vol 706-709 ◽  
pp. 2693-2698 ◽  
Author(s):  
A. Arlazarov ◽  
M. Gouné ◽  
O. Bouaziz ◽  
A. Hazotte ◽  
F. Kegel
Keyword(s):  
Mechanical Behavior ◽  
Annealing Time ◽  
Room Temperature ◽  
Intercritical Annealing ◽  
Tensile Tests ◽  
The Other ◽  
Metastable Austenite ◽  
High Fraction ◽  
Cold Rolled ◽  
Strength And Ductility

The study about the influence of intercritical annealing time on a cold rolled 0.1%C – 4.6%Mn (wt.%) steel was performed. The tensile tests show an interesting balance between strength and ductility especially after 7 hours annealing at 670°C. A part of this good result can be explained by the presence of rather high fraction of metastable austenite at room temperature. On the other hand a very complex microstructure combining lath-like and polygonal features was observed making the interpretation complicated.

scholarly journals Effect of Aerogel Particle Concentration on Mechanical Behavior of Impregnated RTV 655 Compound Material for Aerospace Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Firouzeh Sabri ◽  
Jeffrey G. Marchetta ◽  
K. M. Rifat Faysal ◽  
Andrew Brock ◽  
Esra Roan
Keyword(s):  
Mechanical Behavior ◽  
Room Temperature ◽  
Particle Concentration ◽  
Tensile Tests ◽  
Limiting Factor ◽  
Thermal And Mechanical Properties ◽  
Aerospace Applications ◽  
Elastomeric Matrix ◽  
Compound Material ◽  
And Behavior

Aerogels are a unique class of materials with superior thermal and mechanical properties particularly suitable for insulating and cryogenic storage applications. It is possible to overcome geometrical restrictions imposed by the rigidity of monolithic polyurea cross-linked silica aerogels by encapsulating micrometer-sized particles in a chemically resistant thermally insulating elastomeric “sleeve.” The ultimate limiting factor for the compound material’s performance is the effect of aerogel particles on the mechanical behavior of the compound material which needs to be fully characterized. The effect of size and concentration of aerogel microparticles on the tensile behavior of aerogel impregnated RTV655 samples was explored both at room temperature and at 77 K. Aerogel microparticles were created using a step-pulse pulverizing technique resulting in particle diameters between 425 μm and 90 μm and subsequently embedded in an RTV 655 elastomeric matrix. Aerogel particle concentrations of 25, 50, and 75 wt% were subjected to tensile tests and behavior of the compound material was investigated. Room temperature and cryogenic temperature studies revealed a compound material with rupture load values dependent on (1) microparticle size and (2) microparticle concentration. Results presented show how the stress elongation behavior depends on each parameter.

Influence of Pulsed Current on the Tensile Behaviors of the 5XXX Aluminum Alloy

2014 ◽  
Vol 709 ◽  
pp. 399-402
Author(s):  
Jung Han Song ◽  
Seo Gou Choi
Keyword(s):  
Flow Stress ◽  
Room Temperature ◽  
Test System ◽  
Al Alloys ◽  
Electric Resistivity ◽  
Al Alloy ◽  
Challenging Problem ◽  
Specific Strength ◽  
High Specific Strength ◽  
Strength And Stiffness

Aluminum (Al) alloys have great potential as ideal structural materials because of their high specific strength and stiffness. However, Al alloys exhibit poor ductility at room temperature. Enhancing the formability is a very important and challenging problem to both automotive and manufacturing engineers. In this study, the electro-plastic effects, which is first discovered in 1960s, of 5xxx Al alloy sheets are investigated to improve the formability. To begin with, a test system is built up to carry out the tensile test with heavy electric current flowing through the specimen. The evolutions of the flow stress and the electric resistivity are obtained using this test system. The significant decrease in the flow stress caused by the heavy flowing through current is observed.

Experimental Investigation on the Mechanical Behavior of Polyurethane PICCs after Long-Term Conservation in in Vivo-Like Conditions

2017 ◽  
Vol 18 (6) ◽  
pp. 522-529 ◽  
Author(s):  
Francesca Di Puccio ◽  
Giuseppe Gallone ◽  
Andrea Baù ◽  
Emanuele M. Calabrò ◽  
Simona Mainardi ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Response ◽  
Tensile Tests ◽  
Ethanol Solution ◽  
Uniaxial Tensile ◽  
Research Activity ◽  
Two Fluids ◽  
Weight Variation

Introduction In a previous paper, the authors investigated the mechanical behavior of several commercial polyurethane peripherally inserted central venous catheters (PICCs) in their ‘brand new’ condition. The present study represents a second step of the research activity and aims to investigate possible modifications of the PICC mechanical response, induced by long-term conservation in in vivo-like conditions, particularly when used to introduce oncologic drugs. Methods Eight 5 Fr single-lumen catheters from as many different vendors, were examined. Several specimens were cut from each of them and kept in a bath at 37°C for 1, 2, 3 and 6 months. Two fluids were used to simulate in vivo-like conditions, i.e. ethanol and Ringer-lactate solutions, the first being chosen in order to reproduce a typical chemical environment of oncologic drugs. The test plan included swelling analyses, uniaxial tensile tests and dynamic mechanical thermal analysis (DMTA). Results and conclusions All tested samples were chemically and mechanically stable in the studied conditions, as no significant weight variation was observed even after six months of immersion in ethanol solution. Uniaxial tensile tests confirmed such a response. For each PICC, very similar curves were obtained from samples tested after different immersion durations in the two fluid solutions, particularly for strains lower than 10%.

Numerical Evaluation of Crack in Polyvinylidene Fluoride (PVDF)

2020 ◽  
Author(s):  
Ingrid Cristina S. Pereira ◽  
Celio A. da Costa Neto ◽  
José Renato M. Sousa ◽  
Erica G. Chaves ◽  
Sylvia Teixeira
Keyword(s):  
Numerical Model ◽  
Mechanical Behavior ◽  
Polyvinylidene Fluoride ◽  
Numerical Data ◽  
Tensile Tests ◽  
Plastic Behavior ◽  
Razor Blade ◽  
Material Parameters ◽  
High Degree

Abstract Polyvinylidene fluoride (PVDF) is an engineering thermoplastic having a high degree of sensibility to crack, which affects long-term mechanical behavior. This study evaluates the crack-sensitive of PVDF for one commercial-grade through the development of a numerical model. Firstly, tensile tests using DIC were performed on both uncrack and pre-crack specimens to get experimental tensile as DIC-displacement, displacement-control, and load data. For pre-crack specimens, it was proposed two values of depth: 1.0 and 1.5 mm, opened by razor blade. All specimens were uniaxial tests at 23°C under 5 mm/min. Secondly, tensile tests using extensometer were implemented for uncrack samples to determine material parameters for calibration of the numerical model and comparison with DIC-displacement. Finally, a numerical model based on the FE was implemented using ANSYS-student that inputs PVDF’s material properties, which considered the elastic-plastic behavior in simulation tests. The PVDF demonstrated significant crack sensitivity, as it can be seen in experimental and numerical data. And, the numerical model developed based on MKHP was successfully agreement against experimental data obtained by Blue Hill 3 software. Therefore, the results allowed us to observe that pre-crack acts as a stress concentration and the numerical model got well simulates this influence on the PVDF mechanical behavior.

Determining High-Temperature Oxidation Resistance of (TI-Al-X-N) Based Coatings for Titanium Alloys

2021 ◽  
Vol 320 ◽  
pp. 66-71
Author(s):  
Konstantins Savkovs ◽  
Margarita Urbaha ◽  
Viktors Feofanovs
Keyword(s):  
Titanium Alloys ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Resistance Testing ◽  
Maximum Efficiency ◽  
Temperature Oxidation ◽  
Turbine Engine ◽  
Specific Strength ◽  
High Specific Strength ◽  
Pressure Part

Basic titanium alloys are successfully used in modern aviation GTE (gas turbine engine). They are used for parts of a compressor and partly in low pressure part of turbine (intermetallic Ti-Al alloys) due to their high specific strength and at the same time low density, high corrosion resistance but can be used only up to 700 °C. The paper deals with the results of heat resistance testing at 750 °C of Ti-Al-(X)+N based thin ion-plasm multilayers coatings, with different priority of monolayers- intermetallic, conglomerate or nitride for gas turbine engine (GTE) blades from titanium alloys. All coatings showed high resistance during the test, with a maximum efficiency 42.8 of coating with a priority of conglomerate after 30 hours of testing.

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