Instrumented Indentation Testing to Evaluate High-Temperature Material Properties

2011 ◽  
Author(s):  
Chan-Pyoung Park ◽  
Kug-Hwan Kim ◽  
Seung-Kyun Kang ◽  
Won-Je Jo ◽  
Dongil Kwon
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Material Properties ◽  
Indentation Test ◽  
Temperature Deformation ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Indentation Testing ◽  
Instrumented Indentation ◽  
Uniaxial Tensile Testing

Mechanical properties must be evaluated at high temperatures to predict high-temperature deformation and fracture behavior, since high-temperature properties differ greatly from those at room temperature. A high-temperature uniaxial tensile test, a representative high-temperature test, is generally used, but it has the limitation of obtaining merely the average material properties. Recently an advanced method for evaluating tensile properties has been developed: the instrumented indentation test (IIT), which simultaneously applies a load and measures displacement. Here we use instrumented indentation testing to evaluate the flow properties (yield strength, ultimate tensile strength, etc.) of heat-resistant steel at high temperature. The contact-area determination algorithm and representative stress-representative strain approach are applied for high temperatures. We compare our experimental results to those of conventional high-temperature uniaxial tensile testing to assess the high-temperature performance of the instumented indentation test.

scholarly journals Application of Macro-Instrumented Indentation Test for Superficial Residual Stress and Mechanical Properties Measurement for HY Steel Welded T-Joints

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2061
Author(s):  
Junsang Lee ◽  
Kyungyul Lee ◽  
Seungha Lee ◽  
Oh Min Kwon ◽  
Won-Ki Kang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Yield Strength ◽  
Arc Welding ◽  
Volume Fraction ◽  
Indentation Test ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Indentation Testing ◽  
Instrumented Indentation ◽  
Flux Cored Arc Welding

HY-80 and HY-100 steels, widely used in constructing large ocean vessels and submarine hulls, contain mixed microstructures of tempered bainite and martensite and provide high tensile strength and toughness. Weld integrity in HY steels has been studied to verify and optimize welding conditions. In this study, the T-joint weld coupons, HY80 and HY100, were fabricated from HY-80 and HY-100 steel plates with a thickness of 30 mm as base metals by submerged-arc welding. Flux-cored arc welding was performed on an additional welding coupon consisting of HY-100 to evaluate the effect of repair welds (HY100RP). Microstructures in the heat-affected zones (HAZ) were thoroughly analyzed by optical observation. Instrumented indentation testing, taking advantage of local characterization, was applied to assess the yield strength and the residual stress of the HAZ and base regions. The maximum hardness over 400 HV was found in the HAZ due to the high volume fraction of untempered martensite microstructure. The yield strength of the weld coupons was evaluated by indentation testing, and the results showed good agreement with the uniaxial tensile test (within 10% range). The three coupons showed similar indentation residual stress profiles on the top and bottom surfaces. The stress distribution of the HY100 coupon was comparable to the results from X-ray diffraction. HY100RP demonstrated increased tensile residual stress compared to the as-welded coupon due to the effect of the repair weld (323 and 103 MPa on the top and bottom surfaces). This study verifies the wide applicability of indentation testing in evaluating yield strength and residual stress.

Oxidation Effects during High Temperature Deformation of CP Ti Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 3678-3683
Author(s):  
Ming Jen Tan ◽  
X.J. Zhu ◽  
S. Thiruvarudchelvan ◽  
K.M. Liew
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
High Temperatures ◽  
Pure Titanium ◽  
Initial Strain Rate ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Uniaxial Tensile ◽  
Commercially Pure Titanium ◽  
Commercially Pure

This work reports the influence of oxidation on the superplasticity of commercially pure titanium at high temperatures. Uniaxial tensile tests were conducted at temperatures in the range 600-800°C with an initial strain rate of 10s-1 to 10s-3. This study shows that oxidization at the surface of the alloy causes oxide film on the surface of commercially pure titanium alloy, and the thickness of oxide film increase with increasing exposure time and temperature. XRD analysis shows that the oxide film consists of TiO2. Because this oxide film is very brittle, it can induce clefts and degrade the ductility of the titanium at high temperatures. The mechanism of the initial clefts was investigated and a model for the cleft initiation and propagation during high temperature tensile test was proposed.

A Method for Estimating Uncertainty of Indentation Tensile Properties in Instrumented Indentation Test

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Eun-chae Jeon ◽  
Joo-Seung Park ◽  
Doo-Sun Choi ◽  
Kug-Hwan Kim ◽  
Dongil Kwon
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Tensile Test ◽  
Tensile Properties ◽  
Indentation Test ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Instrumented Indentation ◽  
Estimation Model ◽  
Instrumented Indentation Test

The instrumented indentation test, which measures indentation tensile properties, has attracted interest recently because this test can replace uniaxial tensile test. An international standard for instrumented indentation test has been recently legislated. However, the uncertainty of the indentation tensile properties has never been estimated. The indentation tensile properties cannot be obtained directly from experimental raw data as can the Brinell hardness, which makes estimation of the uncertainty difficult. The simplifying uncertainty estimation model for the indentation tensile properties proposed here overcomes this problem. Though the influence quantities are generally defined by experimental variances when estimating uncertainty, here they are obtained by calculation from indentation load-depth curves. This model was verified by round-robin test with several institutions. The average uncertainties were estimated as 18.9% and 9.8% for the indentation yield strength and indentation tensile strength, respectively. The values were independent of the materials’ mechanical properties but varied with environmental conditions such as experimental instruments and operators. The uncertainties for the indentation yield and tensile strengths were greater than those for the uniaxial tensile test. These larger uncertainties were caused by measuring local properties in the instrumented indentation test. The two tests had the same tendency to have smaller uncertainties for tensile strength than yield strength. These results suggest that the simplified model can be used to estimate the uncertainty in indentation tensile properties.

Multiscale Mapping of Mechanical Properties by Instrumented Indentation Test

2010 ◽  
Vol 654-656 ◽  
pp. 2316-2321
Author(s):  
Kug Hwan Kim ◽  
Young Cheon Kim ◽  
Seung Kyun Kang ◽  
Kwang Ho Kim ◽  
Dong Il Kwon
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Indentation Test ◽  
Uniaxial Tensile ◽  
Material Surface ◽  
Uniaxial Tensile Test ◽  
Instrumented Indentation ◽  
Flow Properties ◽  
Residual Stress State ◽  
Instrumented Indentation Test

The instrumented indentation test (IIT) is a mechanical testing method to determine the hardness and elastic modulus of materials by putting an indenter into a material surface. This technique has now gone beyond normal hardness tests by evaluating additional properties of materials and by allowing testing at much lower forces and indentation depths (micro/nano ranges). This study presents analytic models and procedures for evaluating tensile flow properties and residual stress state using IIT; the tensile flow properties are treated by defining a representative stress/strain beneath a spherical indenter and the residual stress by using a stress-insensitive contact hardness model. The IIT results are compared with those from conventional methods such as uniaxial tensile test and X-ray diffraction. In addition, IIT can be used as a multiscale mapping tool for the mechanical properties of composite materials and constituent phases by using macro/micro/nano indentation system: we made a hardness map of multiphase steel and measured the strength/residual stress distributions of welded pipeline.

scholarly journals Polar poly(n-butyl acrylate)-g-polyacrylonitrile elastomer with high temperature elasticity and healability as flexible electronic substrate

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yuzhu Zheng ◽  
Deli Xu ◽  
Shiyou Tian ◽  
Manli Li ◽  
Wenwen Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Graft Copolymer ◽  
Butyl Acrylate ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Self Healing ◽  
Chemical Structures ◽  
Flexible Electronic ◽  
Ag Nanowires ◽  
Cyano Groups

AbstractIn this work, graft copolymer poly (n-butyl acrylate)-g-polyacrylonitrile with poly (n-butyl acrylate) as backbones and polyacrylonitrile as side chains (PnBA-g-PAN) was synthesized by macromonomer method and emulsion polymerization. The macromonomer was synthesized by atom transfer radical polymerization and end-group modification. The chemical structures and thermal properties of macromonomer and graft copolymer were investigated by FTIR, GPC, NMR and TGA, etc. The mechanical properties of graft copolymer elastomer was also measured by uniaxial tensile test. Rheological properties at different temperature and mechanical property demonstrated that graft copolymer elastomer possessed elasticity until 180 oC because of cyclization of cyano groups. Ag nanowires@PnBA-g-PAN composite elastomer was developed, and the resulted material exhibited autonomic healing property on account of segments’ flexibility and dynamic interaction between Ag nanowires (AgNWs) and cyano groups. This is a general method for generation of elastomer with high temperature elasticity and fast self-healing. The composite elastomer has potential application in flexible electronic conductor.

The Effect of Heat Treatment on Mechanical Properties of Car Interior Fabric Used for Injection Molding

2012 ◽  
Vol 532-533 ◽  
pp. 234-237
Author(s):  
Wei Lai Chen ◽  
Ding Hong Yi ◽  
Jian Fu Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Temperature ◽  
Injection Molding ◽  
High Temperatures ◽  
Material Properties ◽  
Injection Molding Process ◽  
Molding Process ◽  
Composite Fabrics

The purpose of this paper is to study the effect of high temperature in injection molding process on mechanical properties of the warp-knitted and nonwoven composite fabrics (WNC)used in car interior. Tensile, tearing and peeling properties of WNC fabrics were tested after heat treatment under120, 140,160,180°C respectively. It was found that, after 140°C heat treatment, the breaking and tearing value of these WNC fabrics are lower than others. The results of this study show that this phenomenon is due to the material properties of fabrics. These high temperatures have no much effect on peeling properties of these WNC fabrics. It is concluded that in order to preserve the mechanical properties of these WNC fabrics, the temperature near 140°C should be avoided possibly during injection molding process.

Structure Assessment Using Instrumented Indentation: Strength, Toughness and Residual Stress

2018 ◽  
Author(s):  
Dongil Kwon ◽  
Jong Hyoung Kim ◽  
Ohmin Kwon ◽  
Woojoo Kim ◽  
Sungki Choi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Residual Stress ◽  
Tensile Properties ◽  
Hole Drilling ◽  
Uniaxial Tensile ◽  
Small Scale ◽  
Specimen Preparation ◽  
Instrumented Indentation ◽  
Uniaxial Tensile Testing

The instrumented indentation technique (IIT) is a novel method for evaluating mechanical properties such as tensile properties, toughness and residual stress by analyzing the indentation load-depth curve measured during indentation. It can be applied directly on small-scale and localized sections in industrial structures and structural components since specimen preparation is very easy and the experimental procedure is nondestructive. We introduce the principles for measuring mechanical properties with IIT: tensile properties by using a representative stress and strain approach, residual stress by analyzing the stress-free and stressed-state indentation curves, and fracture toughness of metals based on a ductile or brittle model according to the fracture behavior of the material. The experimental results from IIT were verified by comparing results from conventional methods such as uniaxial tensile testing for tensile properties, mechanical saw-cutting and hole-drilling methods for residual stress, and CTOD test for fracture toughness.

Viscoplastic Constitutive Model for High Strain Rate Mechanical Properties of SAC-Q Leadfree Solder After High-Temperature Prolonged Storage

2018 ◽  
Author(s):  
Pradeep Lall ◽  
Vikas Yadav ◽  
Jeff Suhling ◽  
David Locker
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
Thermal Aging ◽  
High Strain ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Aging Effects ◽  
Model Predictions

Electronics in automotive underhood and downhole drilling applications may be subjected to sustained operation at high temperature in addition to high strain-rate loads. SAC solders used for second level interconnects have been shown to experience degradation in high strain-rate mechanical properties under sustained exposure to high temperatures. Industry search for solutions for resisting the high-temperature degradation of SAC solders has focused on the addition of dopants to the alloy. In this study, a doped SAC solder called SAC-Q solder have been studied. The high strain rate mechanical properties of SAC-Q solder have been studied under elevated temperatures up to 200°C. Samples with thermal aging at 50°C for up to 6-months have been used for measurements in uniaxial tensile tests. Measurements for SAC-Q have been compared to SAC105 and SAC305 for identical test conditions and sample geometry. Data from the SAC-Q measurements has been fit to the Anand Viscoplasticity model. In order to assess the predictive power of the model, the computed Anand parameters have been used to simulate the uniaxial tensile test and the model predictions compared with experimental data. Model predictions show good correlation with experimental measurements. The presented approach extends the Anand Model to include thermal aging effects.

Lubrication at High Temperatures With Vapor-Deposited Surface Coatings

1961 ◽  
Vol 83 (2) ◽  
pp. 133-138 ◽  
Author(s):  
D. J. Baldwin ◽  
G. W. Rowe
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
High Temperature ◽  
Boron Nitride ◽  
High Temperatures ◽  
Indentation Test ◽  
Surface Coatings ◽  
Molybdenum Disulphide ◽  
High Coefficient ◽  
Inorganic Films

An experimental study of the friction of metals which have been coated with inorganic films by reaction with their surrounding atmosphere. The specimens are first cleaned at high temperature in vacuo and then heated in the selected reactive vapor. Many coatings will prevent seizure and give a fairly constant but high coefficient of friction up to high temperatures. Layer-lattice compounds such as MoS2, CrCl3, and TiI2 give much lower friction at all temperatures below those at which the film decomposes or evaporates (about 850 C for molybdenum disulphide). A film of boron nitride formed on boron shows a high intrinsic friction, but this can be reduced by certain vapors or by raising the temperature above about 800 C. Most of the experiments were performed with very light loads but the films are shown to be effective under kilogram loads. A simple indentation test capable of selecting lubricants under loads up to 12 tons is described. This shows that a film formed by heating stainless steel in CCl2F2 will lubricate at 400 C when the steel is deformed by over 50 per cent.

Continuity and Affine Fiber Kinematics in Biaxial Tension of the Supraspinatus Tendon

2011 ◽  
Author(s):  
Spencer E. Szczesny ◽  
John Peloquin ◽  
Sarah Ilkhani-Pour ◽  
Daniel H. Cortes ◽  
Jennifer A. Kadlowec ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Material Properties ◽  
Biaxial Tension ◽  
Supraspinatus Tendon ◽  
Recent Analysis ◽  
Uniaxial Tensile ◽  
Angle Distribution ◽  
Fiber Angle ◽  
Uniaxial Tensile Testing

The human supraspinatus tendon (SST) exhibits strong heterogeneity in fiber alignment and material properties [1,2]. The relationship between fiber angle distribution and material properties has been previously described by a structurally based continuum model [3], which provided new quantitative structure-function relationships to explain the observed SST heterogeneity; however, in some locations and testing directions, the model predictions were not consistent with a continuum assumption [3]. More recent analysis of the change in fiber angle during loading showed that samples with less aligned fibers have less affine kinematics in uniaxial tensile loading [4]. That is, in uniaxial tensile testing, where the transverse edges freely contract, the fiber strain did not match the tissue strain. Because the SST is somewhat transversely constrained by surrounding rotator cuff structures in vivo and has distributed fibers to support multidirectional loading, the freely contracting edges of uniaxial tension may not appropriately constrain the tendon. Therefore, the objective of this study was to evaluate SST stress-strain behavior and affine deformation under biaxial tension. Specifically, if behaving as a continuum, we expected that applying a fixed boundary condition in the transverse direction would produce a higher apparent modulus, a smaller toe-region, and more affine fiber realignment than a free boundary condition.

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