Constitutive Equations for Tensile and Creep Behavior of a 9 Cr-1 MO Steel

1975 ◽  
Vol 97 (4) ◽  
pp. 258-263
Author(s):  
F. V. Ellis ◽  
J. E. Bynum ◽  
B. W. Roberts
Keyword(s):  
Constitutive Equation ◽  
Test Data ◽  
Constitutive Equations ◽  
Tensile Tests ◽  
Temperature Dependent ◽  
Creep Tests ◽  
Creep Properties ◽  
Hardening Mechanism ◽  
Strain Relationship ◽  
Analysis Computer

This paper describes an investigation of the tensile and creep properties of annealed 9 Cr-1 Mo steel. Tensile tests were conducted at temperatures from 70 to 1050 F while creep tests were conducted at 750, 850, 950, and 1050 F with stresses from 4 to 52 ksi. From the tensile test data, a constitutive equation was developed for the stress-plastic strain relationship. This equation was based on a two-stage hardening mechanism and combined power law and exponential functions. From the creep test data, isochronous stress-strain curves were constructed out to 104 hr. These curves were extrapolated to 105 hr and to lower stresses using a parametric analysis procedure. Additionally, a creep constitutive equation capable of describing the total creep curve, including the tertiary region, was developed. This equation, having three stress and temperature dependent parameters predicted creep curves which were in good agreement with the actual curves. Both the time-independent (tensile) and time-dependent (creep) constitutive equations are suitable for use in finite element stress analysis computer programs.

scholarly journals Influence of strain rate and heat treatments on tensile and creep properties of Zn-0.15Cu-0.07Ti alloys

DYNA ◽  
2016 ◽  
Vol 83 (195) ◽  
pp. 77-83 ◽  
Author(s):  
María José Quintana Hernández ◽  
José Ovidio García ◽  
Roberto González Ojeda ◽  
José Ignacio Verdeja
Keyword(s):  
Strain Rate ◽  
Room Temperature ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Strain Rates ◽  
Creep Tests ◽  
Design Problems ◽  
Creep Properties ◽  
Heat Treated ◽  
Zn Alloys

The use of Cu and Ti in Zn alloys improves mechanical properties as solid solution and dispersoid particles (grain refiners) may harden the material and reduce creep deformation. This is one of the main design problems for parts made with Zn alloys, even at room temperature. In this work the mechanical behavior of a Zn-Cu-Ti low alloy is presented using tensile tests at different strain rates, as well as creep tests at different loads to obtain the value of the strain rate coefficient m in samples parallel and perpendicular to the rolling direction of the Zn strip. The microstructure of the alloy in its raw state, as well as heat treated at 250°C, is also analyzed, as the banded structure produced by rolling influences the strengthening mechanisms that can be achieved through the treatment parameters.

Thermo-Mechanical Characterizations of Plasma-Sprayed Mcraiy Coatings for HP Turbines

1998 ◽  
Author(s):  
A. Boudot ◽  
F. Crabos ◽  
P. Monge-Cadet ◽  
D. Monceau ◽  
B. Pieraggi
Keyword(s):  
Single Crystal ◽  
Great Influence ◽  
Tensile Tests ◽  
Positive Influence ◽  
Creep Tests ◽  
Creep Properties ◽  
Transition Strain ◽  
Before And After ◽  
Coating Microstructure ◽  
Plasma Sprayed

Abstract Two different coatings were studied in this work : vacuum plasma-sprayed NiCoCrAlYTa and electrodeposited NiCoCrAlYTa. These coatings were deposited on AM3 single crystal alloy. The tensile and creep properties of coated single crystal test specimens were investigated. DBlT were determined from tensile tests. Creep tests were performed on cylindrical specimens and on thin flat specimens. All the coatings were examined before and after testing. The two tested coatings induce a ductile/brittle transition. Strain rate has a great influence on the transition temperature. The comparison between the two processes of deposition illustrates the strong influence of coating microstructure. A marked decrease in creep properties was observed for thin single crystal specimens but contrary to cylindrical specimens, the coating has a quite positive influence, so that the creep life of coated thin specimens is increased.

A Finite Element Study of Friction Effect in Four-Point Bending Creep Test

2003 ◽  
Author(s):  
Young Suk Kim ◽  
Don R. Metzger
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Creep Test ◽  
Contact Point ◽  
Simulation Studies ◽  
Creep Tests ◽  
Contact Conditions ◽  
Creep Properties ◽  
Four Point Bending ◽  
Bend Tests

Creep tests are often performed in four-point bending and the stress distribution in the bending specimen is nonlinear, so creep properties are estimated from bend creep test data. However, getting creep properties from bending creep tests is often doubted because of uncertainties from contact point shift and frictional effect between loading pin and specimen in four-point bending creep tests. Finite element simulations of the four-point bending creep tests were performed with geometric models which include contact conditions. It was found from simulation studies that friction in the bend tests can cause error in the estimation of creep properties, but when no friction was applied in simulations the creep properties were well predicted from bend test data.

High Temperature Properties and Constitutive Equations for 1 Cr-1/2 Mo Steel

1978 ◽  
Vol 100 (3) ◽  
pp. 246-255 ◽  
Author(s):  
Saphura S. Long
Keyword(s):  
Creep Rate ◽  
Constitutive Equation ◽  
Constitutive Equations ◽  
Minimum Creep Rate ◽  
Room Temperature ◽  
Tensile Tests ◽  
Creep Rupture ◽  
Secondary Creep ◽  
Stress Strain ◽  
Plastic Strain Range

This paper presents the tensile, creep, rupture, and fatigue properties of 1 Cr-1/2 Mo steel. Tensile tests were conducted over a temperature range of 70–1150 F (21 to 621 C). Creep-rupture tests were run for the stress range of 10–56 ksi (69 to 386 MPa) at temperatures of 850 to 1150 F (454 to 621 C) and the strain-controlled fatigue tests were run to 145,000 cycles at room temperature. Results of the tensile tests are presented as stress-strain curves and as constitutive equations. The parameters in the equations were obtained by a nonlinear least-squares technique assuming an origin offset power law formulation of true stress as a function of true strain. The creep analysis resulted in a creep constitutive equation, isochronous stress-strain curves, and correlations between rupture time, time to onset of tertiary creep, and minimum creep rate. The constitutive equation is a two-term rational polynomial with a steady-state term which describes primary plus secondary creep. Isochronous stress-strain curves were developed from the creep equation and extrapolated to 100,000 hr. Over the measured range, the isochronous curves showed excellent agreement with the actual data. In absolute strength level, both the rupture stress and minimum creep rate data show that this particular heat of material lies in the upper part of the scatter band for 1 Cr-1/2 Mo steel. The room temperature cyclic stress-strain curves show the alloy strain softens in the low strain region and strain hardens in the high-strain region. The fatigue behavior is typified by a linear relationship between both elastic and plastic strain range and cycles to failure on a log-log basis. The fatigue results conform reasonably well to predictions from Manson’s method of universal slopes.

scholarly journals The microstructure and creep properties of as-cast Mg-Sn-Si-(Al) magnesium alloys

2020 ◽  
Vol 20 (3) ◽  
Author(s):  
Tomasz Rzychoń
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Ambient Temperature ◽  
Tensile Properties ◽  
Magnesium Alloys ◽  
Creep Resistance ◽  
Solution Treatment ◽  
Tensile Tests ◽  
Creep Tests ◽  
Creep Properties

Abstract Magnesium alloys containing rare earth metals exhibit good creep resistance up to 300 °C and good tensile properties at ambient temperature. The high cost of rare earth has led to studies regarding the creep resistance of Mg alloys with cheap alloying elements (Sn, Ca, Si) that could be substituted for Mg-RE alloys. In this paper, the influence of Si and Al on microstructure and mechanical properties of Mg-7Sn alloy was investigated using optical (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), tensile tests and creep tests at 200–250 °C. Microstructure of as-cast alloys consists of α-Mg matrix and intermetallic compounds at the interdendritic regions. Heat treatment consisting of solid solution treatment and ageing increases the tensile properties at ambient temperature due to the precipitation of the fine Mg2Sn phase. The creep resistance of aged Mg-7Sn alloy is poor. The addition of Si and Al to Mg-7Sn alloy has resulted in improving the creep resistance due to the refinement of Mg2Sn phase and the appearance of Mg2Si phase at the grain boundaries. The Mg-7Sn-1Si alloy exhibits better creep resistance at 200 °C than Mg-7Sn-5Si and Mg-7Sn-5Si-2Al alloys. The Mg-7Sn alloys with 5% Si have better creep properties at 250 °C in comparison to Mg-7Sn-1Si alloy.

Modelling and Data Interpretation of Small Punch Creep Testing

2011 ◽  
Author(s):  
R. Li ◽  
T. H. Hyde ◽  
W. Sun ◽  
B. Dogan
Keyword(s):  
Large Deformation ◽  
Test Data ◽  
Creep Test ◽  
Creep Model ◽  
Test Results ◽  
Creep Tests ◽  
Creep Properties ◽  
Small Punch ◽  
Draft Code ◽  
Uniaxial Creep

The small punch testing (SPT) technique has been proposed for use in determining the creep properties of materials for which only a very small volume of material is available. A draft code of practice on SPT has been produced. However it is not, as yet, generally accepted that the data obtained from small punch tests can be directly related to those which would be obtained from conventional uniaxial creep tests. For this reason, the development of techniques suitable for the interpretation of SPT data has become very important. In this paper, a set of uniaxial creep test data has been characterised in such a way as to gain an improved understanding of the correlation between the data from small punch tests and corresponding uniaxial creep tests. Finite element (FE) analyses of small punch creep tests, using a damage mechanics based creep model, have been performed. The effect of large deformation on the determination of material properties for a creep damage model, has been investigated to take into account the large deformation nature of small punch tests. An equivalent stress, σeq, proposed by the draft code, was used to relate the SPT results to the corresponding uniaxial creep test results. A preliminary assessment of the use of small punch test results, in determining creep properties, has been presented, which includes comparisons of the failure life and equivalent minimum strain rate results obtained from SPTs with the corresponding uniaxial creep test data. Future work related to the interpretation of SPT is briefly addressed.

Statistical analysis of creep behavior in thermoset and thermoplastic composites reinforced with carbon and glass fibers

2020 ◽  
pp. 030932472097663
Author(s):  
Francisco Maciel Monticeli ◽  
Ana Karoline dos Reis ◽  
Roberta Motta Neves ◽  
Luis Felipe de Paula Santos ◽  
Edson Cocchieri Botelho ◽  
...  
Keyword(s):  
Creep Behavior ◽  
Glass Fibers ◽  
Laminated Composite ◽  
Analytical Models ◽  
Thermoplastic Composites ◽  
Temperature Dependent ◽  
Creep Tests ◽  
Thermoset Composites ◽  
Strain Behavior ◽  
Sensitivity Range

The thermoplastic and thermoset laminates reinforced with different fibers generate variations in the laminated composite mechanical behavior. This work aims to analyze thermoplastic and thermoset composites creep behavior with a reduced number of experiments, applying curve-fitting analytical models (Weibull and Findley) and statistical approach (ANOVA, F-test, and SRM) in order to describe creep behavior. Creep tests were carried out using a design of experiments to define parameter levels, aiming to reduce the number of the experiments, keeping reliability relevance. The temperature shows a stronger influence of creep deformation compared with the use of distinct materials. Thermoplastic matrices seem to be more sensitive to deformation, decreasing the reinforcement contribution. On the other hand, the creep resistance of the thermoset matrix conducts a significant contribution of strain behavior for the reinforcement used. The Findley model showed a temperature-dependent response. While, the Weibull-based model exhibits temperature and material-dependence, ensuring a greater sensitivity range of the parameters applied, an essential factor for a more realistic method description.

Creep Properties and Interfacial Microstructure of SiC Whisker Reinforced Si3N4

1989 ◽  
Vol 170 ◽  
Author(s):  
Håkan A. Swan ◽  
Colette O'meara
Keyword(s):  
High Temperature ◽  
Creep Resistance ◽  
Interfacial Microstructure ◽  
Deformation Mechanisms ◽  
Amorphous Films ◽  
Creep Tests ◽  
Creep Properties ◽  
High Temperature Exposure ◽  
Temperature Exposure

AbstractPreliminary creep tests were performed on SiC whisker reinforced and matrix Si3N4 material fabricated by the NPS technique. The material was extensively crystallised in the as received material, leaving only thin amorphous films surrounding the grains. No improvement in the creep resistance could be detected for the whisker reinforced material. The deformation mechanisms were found to be that of cavitation in the form of microcracks, predominantly at the whisker/matrix interfaces, and the formation of larger cracks. Extensive oxidation of the samples, as a result of high temperature exposure to air, was observed for the materials tested at 1375°C.

Establishment of an ANSYS-Based Constitutive Modeling for Age Forming of Aluminum Alloy

2012 ◽  
Vol 217-219 ◽  
pp. 1497-1500 ◽  
Author(s):  
Xiao Jun Zuo ◽  
Jun Chu Li ◽  
Da Hai Liu ◽  
Long Fei Zeng
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Equation ◽  
Material Model ◽  
Tensile Tests ◽  
Material Constants ◽  
Tensile Process ◽  
Simulation Based ◽  
Optimal Material ◽  
Two Stages ◽  
Good Agreement

Constructing accurate constitutive equation from the optimal material constants is the basis for finite element numerical simulation. To accurately describe the creep ageing behavior of 2A12 aluminum alloy, the present work is tentatively to construct an elastic-plastic constitutive model for simulation based on the ANSYS environment. A time hardening model including two stages of primary and steady-state is physically derived firstly, and then determined by electronic creep tensile tests. The material constants within the creep constitutive equations are obtained. Furthermore, to verify the feasibility of the material model, the ANSYS based numerical scheme is established to simulate the creep tensile process by using the proposed material model. Results show that the creep constitutive equation can better describe the deformation characteristics of materials, and the numerical simulations and experimental test points are in good agreement.

Heat Treatments Effect on the Mechanical Properties of Industrial Drawn Copper Wires

2013 ◽  
Vol 811 ◽  
pp. 9-13 ◽  
Author(s):  
Zakaria Boumerzoug ◽  
Zakaria Boumerzoug ◽  
Vincent Ji
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Treatment Time ◽  
Void Formation ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Ambient Atmosphere ◽  
Creep Tests ◽  
Prior Heat Treatment ◽  
Industrial Material

In this present investigation, the mechanical properties of industrial drawn copper wires have been studied by creep tests, tensile tests and hardness Vickers. The effect of prior heat treatments at 500°C for different time on the drawn wires behavior was the main goal of this investigation. We have found that these heat treatments influenced the creep behavior of drawn wires and recorded shape curves. The creep tests were applied under ambient atmosphere at 240 °C. The creep duration before rupture decreased with the prior heat treatment time. The creep tests results were confirmed by tensile tests. A relationship between the hardness and the ultimate tensile strength of this industrial material has been established. Optical and scanning electron microscopy observations have been also used. Cross section observations of the wire after tensile or creep-rupture tests have shown that the mechanism of rupture was mainly controlled by the void formation.

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