Experimental Investigation of Ti-6Al-4V with a Biaxial Tensile Test Setup at Elevated Temperature

2014 ◽  
Vol 622-623 ◽  
pp. 273-278 ◽  
Author(s):  
Marion Merklein ◽  
Sebastian Suttner ◽  
Adam Schaub

The requirement for products to reduce weight while maintaining strength is a major challenge to the development of new advanced materials. Especially in the field of human medicine or aviation and aeronautics new materials are needed to satisfy increasing demands. Therefore the titanium alloy Ti-6Al-4V with its high specific strength and an outstanding corrosion resistance is used for high and reliable performance in sheet metal forming processes as well as in medical applications. Due to a meaningful and accurate numerical process design and to improve the prediction accuracy of the numerical model, advanced material characterization methods are required. To expand the formability and to skillfully use the advantage of Ti-6Al-4V, forming processes are performed at elevated temperatures. Thus the investigation of plastic yielding at different stress states and at an elevated temperature of 400°C is presented in this paper. For this reason biaxial tensile tests with a cruciform shaped specimen are realized at 400°C in addition to uniaxial tensile tests. Moreover the beginning of plastic yielding is analyzed in the first quadrant of the stress space with regard to complex material modeling.

Author(s):  
Y. Huang ◽  
J. Huang ◽  
J. Cao

Magnesium alloy sheet has received increasing attention in automotive and aerospace industries. It is widely recognized that magnesium sheet has a poor formability at room temperature. While at elevated temperature, its formability can be dramatically improved. Most of work in the field has been working with the magnesium sheet after annealed around 350°C. In this paper, the as-received commercial magnesium sheet (AZ31B-H24) with thickness of 2mm has been experimentally studied without any special heat treatment. Uniaxial tensile tests at room temperature and elevated temperature were first conducted to have a better understanding of the material properties of magnesium sheet (AZ31B-H24). Then, limit dome height (LDH) tests were conducted to capture forming limits of magnesium sheet (AZ31B-H24) at elevated temperatures. An optical method has been introduced to obtain the stress-strain curve at elevated temperatures. Experimental results of the LDH tests were presented.


2011 ◽  
Vol 146 ◽  
pp. 12-26 ◽  
Author(s):  
A. Gherissi ◽  
R.Ben Cheikh ◽  
E. Dévaux ◽  
Fethi Abbassi

In this study, we present the manufacturing process of two new composites materials in the form of long fibers of polylactic-acid (PLA) or polypropylene (PP), reinforced by cellulose whiskers micro-fibers loads. In order to evaluate the mechanical properties of these advanced materials, a several uniaxial tensile tests were carried out. The PP and the PLA have initially been spinning without the addition of cellulose whiskers micro-fibers. In order to study the effects of cellulose whiskers micro-fibers reinforcements in the Mechanical behavior of the PLA and PP filaments, we determinate the proprieties of these advanced material from the tensile results. For the PP composite filaments material case, the whiskers reinforcement increases Young's modulus and failure resistance, but it reduces the limit strength failure. For the PLA composites the addition of 1% wt of cellulose whiskers from the total volume fraction of the material, increase the Young’s modulus more than 50% and a decrease of the failure resistance and the limit strength of composite. The obtained composites fibers are very rigid and brittle. What follows, that the addition of cellulose whiskers micro fibers in PP matrix, provides mechanical properties more convenient compared to the PLA matrix.


2019 ◽  
Vol 54 (13) ◽  
pp. 1705-1715
Author(s):  
MHR Jen ◽  
GT Kuo ◽  
YH Wu ◽  
YJ Chen

The mechanical properties and fatigue responses of Ti/APC-2 neat and nanocomposites with inclined single-edged cracks due to tensile and cyclic tests at elevated temperature were investigated. Two types of composite laminates [Ti/(0/90)s/Ti] were fabricated with and without (W/WO) nanoparticles SiO2 of optimal 1 wt.%. The geometry and dimensions of specimens were L × W × t = 240 × 25 × 1.55 mm3. The cracks were of constant length 3 mm and width 0.3 mm. The inclined angles were 0°, 45°, and 60°. Both the tensile and cyclic tests were conducted at elevated temperatures 25℃ (RT), 100℃, 125℃, and 150℃. From the tensile tests we obtained the load vs. displacement curves for both types of laminates with varied inclinations at elevated temperatures. Next, we received the applied load vs. cycles curves for the same laminates with inclined cracks at the corresponding temperature due to cyclic tests. According to the experimental data of both tensile and cyclic tests the mechanical properties, such as strength, stiffness, and life, decreased as the temperature rises. The greater the inclined angles were, the greater the strength and stiffness were. Similarly, the fatigue life was in the same trend. However, the effect of inclined angle on mechanical properties was more strong than those of temperature. The mechanical properties of nanocomposite laminates were higher than those of neat composite laminates, but not significant. The main reason was that the enhancement of spreading nano-powder silica on the laminate interfaces did not effectively eliminate the stress intensity at the crack tip locally.


Author(s):  
J. Brnic ◽  
M. Canadija ◽  
G. Turkalj ◽  
D. Lanc

In this paper, some interesting, experimentally determined actualities referring to the 50CrMo4 steel are presented. That way, the mechanical properties of the material are derived from uniaxial tensile tests at lowered and elevated temperatures. Engineering stress versus strain diagrams for both mentioned temperatures, curves representing the effect of temperature on specimen elongation, and short-time creep curves are given. Notch impact energy test was also carried out. Taking into consideration the service life of the final product of the mentioned steel widely used in engine and machine technology, all of the mentioned data may be relevant during design and manufacturing procedure.


1970 ◽  
Vol 37 (3) ◽  
pp. 765-770 ◽  
Author(s):  
A. B. Schultz

The mechanical behavior of metals subjected to uniaxial tensile impact at elevated temperatures is reported. Tests were conducted on annealed 1100 aluminum at 200, 350, 550, and 800 deg F; annealed 2024 aluminum at 200, 450, and 600 deg; and annealed C1010 steel at 430, 700, 1050, and 1400 deg F. The materials exhibit a wide range of dynamic behavior, including some in which the stress required to produce a given level of strain is significantly lowered by dynamic loading. The ratios of the dynamic ultimate stresses to the static are found to range from 0.71–6.0.


Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 884 ◽  
Author(s):  
Seyed Vahid Sajadifar ◽  
Emad Scharifi ◽  
Ursula Weidig ◽  
Kurt Steinhoff ◽  
Thomas Niendorf

This study focuses on the high temperature characteristics of thermo-mechanically processed AA7075 alloy. An integrated die forming process that combines solution heat treatment and hot forming at different temperatures was employed to process the AA7075 alloy. Low die temperature resulted in the fabrication of parts with higher strength, similar to that of T6 condition, while forming this alloy in the hot die led to the fabrication of more ductile parts. Isothermal uniaxial tensile tests in the temperature range of 200–400 °C and at strain rates ranging from 0.001–0.1 s−1 were performed on the as-received material, and on both the solution heat-treated and the thermo-mechanically processed parts to explore the impacts of deformation parameters on the mechanical behavior at elevated temperatures. Flow stress levels of AA7075 alloy in all processing states were shown to be strongly temperature- and strain-rate dependent. Results imply that thermo-mechanical parameters are very influential on the mechanical properties of the AA7075 alloy formed at elevated temperatures. Microstructural studies were conducted by utilizing optical microscopy and a scanning electron microscope to reveal the dominant softening mechanism and the level of grain growth at elevated temperatures.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yong Peng ◽  
Xuanzhen Chen ◽  
Shan Peng ◽  
Chao Chen ◽  
Jiahao Li ◽  
...  

In order to study the dynamic and fracture behavior of 6005 aluminum alloy at different strain rates and stress states, various tests (tensile tests at different strain rates and tensile shearing tests at five stress states) are conducted by Mechanical Testing and Simulation (MTS) and split-Hopkinson tension bar (SHTB). Numerical simulations based on the finite element method (FEM) are performed with ABAQUS/Standard to obtain the actual stress triaxialities and equivalent plastic strain to fracture. The results of tensile tests for 6005 Al show obvious rate dependence on strain rates. The results obtained from simulations indicate the feature of nonmonotonicity between the strain to fracture and stress triaxiality. The equivalent plastic strain reduces to a minimum value and then increases in the stress triaxiality range from 0.04 to 0.30. A simplified Johnson-Cook (JC) constitutive model is proposed to depict the relationship between the flow stress and strain rate. What is more, the strain-rate factor is modified using a quadratic polynomial regression model, in which it is considered to vary with the strain and strain rates. A fracture criterion is also proposed in a low stress triaxiality range from 0.04 to 0.369. Error analysis for the modified JC model indicates that the model exhibits higher accuracy than the original one in predicting the flow stress at different strain rates. The fractography analysis indicates that the material has a typical ductile fracture mechanism including the shear fracture under pure shear and the dimple fracture under uniaxial tensile.


Author(s):  
Christopher R. Baker ◽  
Emmanuel Maillet ◽  
Gregory N. Morscher ◽  
Andrew L. Gyekenyesi ◽  
Sung R. Choi ◽  
...  

Foreign object damage in gas turbines presents serious safety and financial concerns. As the aerospace industry draws closer to implementing ceramic matrix composites (CMCs) in gas turbines, the corresponding behavior in these materials after such events needs to be understood. To address this requirement, several silicon infiltrated fiber reinforced SiC/SiC coupons were impacted with high speed projectiles with velocities up to 360 m/s with an impact rig built at the University of Akron and NAVAIR. The resulting damage states were assessed using several non-destructive evaluation (NDE) techniques and compared to actual damage condition observed through the sectioning of impacted coupons. Ultimately, the true consequence of the damage was revealed by measuring the post-impact, residual strengths via uniaxial tensile tests to failure at both room and elevated temperatures. Lastly, the NDE results revealed a complicated damage morphology consisting of in-and-out-of plane damage that significantly affected the retained mechanical properties.


Author(s):  
Tao Chen ◽  
Xuedong Chen ◽  
Juan Ye ◽  
Xiyun Hao

Centrifugal cast 25Cr35Ni-Nb alloy furnace tubes with different contents of S are selected to investigate effects of S addition on creep and fracture behavior. Rupture tests in air at 1100 °C and 17 MPa and slow rate tensile tests at 850 °C showed that the presence of S decreased the creep rupture life and elevated temperature ductility of 25Cr35Ni-Nb alloy obviously. Scanning electron micrographs (SEM) of the fracture and energy dispersive X-ray spectroscopy (EDS) analysis results indicated that S was the important element to control creep rupture life and elevated temperature ductility. S segregated to grain boundaries at elevated temperatures, blocky fine sulfide particles with smooth surface distribute on the grain boundaries. The presence of sulfides became effective nucleation sites for intergranular creep cavities. Micro cracks occurred by linking up cavities at elevated temperatures due to local stress concentration. Eventually, early failure happened.


2018 ◽  
Vol 5 (1) ◽  
pp. 17-00577-17-00577 ◽  
Author(s):  
Masato IIMORI ◽  
Hiro TANAKA ◽  
Mayuko KIMURA ◽  
Yoji SHIBUTANI ◽  
Yang LIU

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