Dynamic Behavior of Metals Under Tensile Impact—Part 1: Elevated Temperature Tests

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.

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.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1217
Author(s):  
Yameng Ji ◽  
Yanpeng Yuan ◽  
Weizheng Zhang ◽  
Yunqing Xu ◽  
Yuwei Liu

In order to evaluate the elevated temperature creep performance of the ABOw/Al–12Si composite as a prospective piston crown material, the tensile creep behaviors and creep fracture mechanisms have been investigated in the temperatures range from 250 to 400 °C and the stress range from 50 to 230 MPa using a uniaxial tensile creep test. The creep experimental data can be explained by the creep constitutive equation with stress exponents of 4.03–6.02 and an apparent activation energy of 148.75 kJ/mol. The creep resistance of the ABOw/Al–12Si composite is immensely improved by three orders of magnitude, compared with the unreinforced alloy. The analysis of the ABOw/Al–12Si composite creep data revealed that dislocation climb is the main creep deformation mechanism. The values of the threshold stresses are 37.41, 25.85, and 17.36 at elevated temperatures of 300, 350 and 400 °C, respectively. A load transfer model was introduced to interpret the effect of whiskers on the creep rate of this composite. The creep test data are very close to the predicted values of the model. Finally, the fractographs of the specimens were analyzed by Scanning Electron Microscope (SEM), the fracture mechanisms of the composites at different temperatures were investigated. The results showed that the fracture characteristic of the ABOw/Al–12Si composite exhibited a macroscale brittle feature range from 300 to 400 °C, but a microscopically ductile fracture was observed at 400 °C. Additionally, at a low tensile creep temperature (300 °C), the plastic flow capacity of the matrix was poor, and the whisker was easy to crack and fracture. However, during tensile creep at a higher temperature (400 °C), the matrix was so softened that the whiskers were easily pulled out and interfacial debonding appeared.


2016 ◽  
Vol 866 ◽  
pp. 88-93
Author(s):  
B. Geethakumari ◽  
R. Ramesh Kumar ◽  
V. Syam Prakash

The influence of three mineral admixtures, Silica Fume (SF), Fly Ash (FA), and Rice Husk Ash (RHA) on the fracture energy of Refractory Cement (RC) over a wide range of temperature from 300K to 1173K is studied. The optimum percentage replacement of RC by these admixtures is found to be around 0.5 for all the temperatures considered but for FA. Fracture energy of control (0% admixture) and blended RC (with 0.5% admixture) are determined by three point bending of notched beam specimens. Fracture energy of RC blended with the three mineral admixtures is lower than that of control RC for temperature range of 300K to 873K. But at elevated temperature of 1173K, blending plays its role as an admixture. Experimental results are corroborating with XRD. It is observed that phenomenon of pseudo dryness of Gismondine in the blended RC causes higher fracture energy which is double that of RC only at 1173K.


2015 ◽  
Vol 32 (4) ◽  
pp. 391-399
Author(s):  
J. Huang ◽  
Y. Yuan ◽  
H. Liu ◽  
J. Cao

AbstractMagnesium (Mg) alloy sheet has received increasing attention in automotive, transportation, 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. To better understand the warm forming properties of magnesium alloy sheet, an accurate description of the mechanical behavior at elevated temperature is required.In this paper, both uniaxial tensile tests and uniaxial compression tests were carried out at warm temperature for Mg AZ31B alloy sheets. The tensile tests were conducted under various strain rates and material orientations, while the compression tests only considered different material orientations. Based on the orthotropic yield criterion for hexagonal close packed (HCP) metals proposed by Cazacu et al., 2006, a viscoplasticity model has been developed to describe the initial yield anisotropy and asymmetry hardening behavior in tensile and compression of Mg sheet. This model was incorporated into ABAQUS through a user-defined material subroutine. The numerical results show a good agreement with experimental data in a large range of deformation.


2016 ◽  
Vol 854 ◽  
pp. 112-117
Author(s):  
Sebastian Suttner ◽  
Marion Merklein

The use of new materials, e.g. aluminum and magnesium alloys, in the automotive and aviation sector is becoming increasingly important to reach the global aim of reduced emissions. Especially magnesium alloys with their low density offer great potential for lightweight design. However, magnesium alloys are almost exclusively formable at elevated temperatures. Therefore, material characterization methods need to be developed for determining the mechanical properties at elevated temperatures. In particular, cyclic tests at elevated temperatures are required to identify the isotropic-kinematic hardening behavior, which is important for numerically modeling the springback behavior. In this contribution, a characterization method for determining the cyclic behavior of the magnesium alloy AZ31B at an elevated temperature of 200 °C is presented. The setup consists of a miniaturized tensile specimen and stabilization plates to prevent buckling under compressive load. The temperature in the relevant area is introduced with the help of conductive heating. Moreover, the complex kinematic model according to Chaboche and Rousselier is identified, to map the transient hardening behavior of AZ31B after load reversal, which cannot be modeled with a single Bauschinger coefficient.


2005 ◽  
Vol 475-479 ◽  
pp. 373-376
Author(s):  
Dong Woo Suh ◽  
Sung Man Sohn ◽  
Moon Yong Lee ◽  
Sang Yong Lee

The deformation behaviors of fully annealed or T6-treated 6061 and 7075 aluminum tubes are investigated at elevated temperature using uniaxial tensile test. Fully annealed 6061 and 7075 tube, and T6-treated 7075 tube do not show sharp local necking with an elongation of 50% at tensile temperature of 300oC, accordingly, it is expected that warm hydroforming process can be applied. The increase of tensile temperature does not significantly affect the total elongation of T6-treated 6061 tube.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
N. K. Mishra ◽  
Naveen Kumar ◽  
S. B. Mishra

Hot corrosion is the major degradation mechanism of failure of boiler and gas turbine components. These failures occur because of the usage of wide range of fuels such as, coal and oil at the elevated temperatures. Nickel based superalloys having excellent mechanical strength and creep resistance at elevated temperature are used under such environment but they lack resistance to hot corrosion at high temperature. To overcome these problems hot corrosion resistant coatings are deposited on these materials. In the current investigation Al2O3-40%TiO2 powder has been deposited on Superni 718 and AE 435 superalloys by Detonation Gun method. The hot corrosion performance of Al2O3-40%TiO2 coated as well as uncoated Superni 718 and AE 435 alloys has been evaluated in aggressive environment Na2SO4-82%Fe2(SO4)3 under cyclic conditions at an elevated temperature of 900°C. The kinetics of the corrosion is approximated by weight change measurements made after each cycle for total duration of 50 cycles. Scanning electron microscopy was used to characterize the hot corrosion products. The coated samples imparted better hot corrosion resistance than the uncoated ones. The AE 435 superalloy performed better than Superni 718 for hot corrosion in a given environment.


2006 ◽  
Vol 976 ◽  
Author(s):  
Junya Inoue ◽  
Yousuke Fujii ◽  
Toshihiko Koseki

AbstractIn this study, mechanical behavior of nanocrystalline Cu alloy thin films under constant tensile strain is studied, by taking advantage of the enhanced resistance to strain localization of a thin metal film on a thick elastomer with appropriate Young's modulus. Cu and Cu alloy thin films with a thickness of 100nm were deposited on heat-resistant polyimide substrates. On the top of the Cu alloy layer, Ta thin film was further deposited to suppress the surface diffusion of Cu alloy. A uniform uniaxial tensile strain was induced to the films by applying a constant radius of curvature to the polyimide substrate. Isothermal deformation and rupture modes of the films were studied by keeping the samples at various elevated temperatures. Microstructural observation was carried out using SEM, TEM, STEM, and confocal violet laser microscope at several stages of deformation. From the observation, the evolution of damage in the sub-critical strain level and the effect of alloying elements are discussed.


Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 123 ◽  
Author(s):  
Zhubin He ◽  
Zhibiao Wang ◽  
Peng Lin

In order to thoroughly understand the quantitative relationships between the flow stress and deformation conditions for Ti2AlNb-based alloys at elevated temperatures, the Arrhenius and Johnson–Cook constitutive models are analyzed and identified on the basis of the uniaxial tensile tests. The Johnson–Cook model is modified so that the referenced temperature range can be randomly adjusted. By experimental verification, the Arrhenius model (including the Backofen model) is suitable for the deformation at relatively low strain-rate deformation, such as the superplastic forming, and the modified J–C model is applicable for the deformation within a wide range of strain rates. For deformation at high temperatures, the constitutive model enables a more precise description of the effect of strain on the flow stress through introducing as train-softening factor exp(sε).


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