US20050066702A1 - Method for measuring elastic properties - Google Patents

Method for measuring elastic properties Download PDF

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US20050066702A1
US20050066702A1 US10917391 US91739104A US2005066702A1 US 20050066702 A1 US20050066702 A1 US 20050066702A1 US 10917391 US10917391 US 10917391 US 91739104 A US91739104 A US 91739104A US 2005066702 A1 US2005066702 A1 US 2005066702A1
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method
max
correction term
dot over
contact
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Gang Feng
Alfonso Ngan
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Gang Feng
Ngan Alfonso Hing Wan
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/40Investigating hardness or rebound hardness
    • G01N3/42Investigating hardness or rebound hardness by performing impressions under a steady load by indentors, e.g. sphere, pyramid
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y35/00Methods or apparatus for measurement or analysis of nanostructures
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02Details not specific for a particular testing method
    • G01N2203/026Specifications of the specimen
    • G01N2203/0286Miniature specimen; Testing on microregions of a specimen

Abstract

This invention relates to a method for measuring elastic modulus of a sample object. This invention also relates to a method for correcting creep effects in the modulus measurement. The error due to creep in the apparent contact compliance is equal to the ratio of the indenter displacement rate at the end of the load hold to the unloading rate. Determination of this error term and deduction of it from the measured contact compliance can be easily done at a low cost by modifying the data analysis software in any commercial depth-sensing indentation system.

Description

    CROSS-REFERENCE TO RELATED APPLICATION
  • This application is a continuation of U.S. patent application Ser. No. 10/300,323 filed Nov. 20, 2002, which is now allowed.
  • FIELD OF THE INVENTION
  • This invention relates generally to a method for measuring elastic properties of a material. More specifically, this invention relates to a method for measuring elastic modulus of a solid material by depth-sensing indentation. In addition, the present invention relates to a method for correcting for the effects of creep when measuring the elastic modulus of a solid material by depth-sensing indentation.
  • BACKGROUND OF THE INVENTION
  • Depth-sensing indentation systems have been used for measuring modulus of various materials. Most commercially available depth-sensing indentation systems are also known as “nanoindentators”. When a nanoindentator is used, the indent size can be made to fall in the sub-micron range. As a result, ultra-small volumes of materials, e.g., second-phase particles in a matrix, thin-films deposited on substrates, etc., can be tested.
  • Unlike other conventional hardness testers, depth-sensing indentation systems use a depth-sensing machine to record the indenter displacement (or the “depth”) data as the indentation proceeds. Many well-known brand names of commercial nanoindenters, such as those manufactured by MTS Systems Corporation, Hysitron Inc. and CSEM Instruments, all use the Oliver-Pharr scheme in their analysis packages. In the Oliver-Pharr scheme, the load and the depth data can be analyzed to give the contact area as well as the contact stiffness between the indenter and the sample. The contact area can be used to compute the hardness of the sample, while the contact stiffness can be used to compute the elastic modulus of the sample.
  • In the Oliver-Pharr scheme, the contact stiffness between the indenter tip and the sample is estimated in an unloading process from the peak load assuming that the material recovery during the unloading process is purely elastic. The reduced modulus Er for the contact between the indenter tip and the sample is calculated from the contact stiffness S at the onset of the unloading process as follows: E r = π 2 S A c ( 1 )
    wherein Ac can be the contact area at full load. The contact area Ac is calculated from the contact depth hc by assuming a shape function of the indenter, i.e., A c = f ( h c ) , h c = h max - ɛ P max S ( 2 )
    wherein ε is a constant depending on the indenter geometry (e.g., ε=0.75 for the Berkovich tip). The reduced modulus Er is related to the sample Young's modulus as follows: 1 E r = 1 - v s 2 E s + 1 - v t 2 E t ( 3 )
    wherein Es=Young's modulus of the sample object, vs=Poisson's ratio of the sample object, Et=Young's modulus of the indenter tip, vt=Poisson's ratio of the indenter tip. In the Oliver-Pharr scheme, the contact stiffness to be used in the above equations (1) and (2) is the observed (or apparent) contact stiffness Su at the onset of the unloading process.
  • In reality, however, significant creep can occur at the peak load even for metals at room temperature after long holding periods. As shown in FIGS. 2(a) and 2(b), the indenter displacement continues to creep in both cases even after a long holding period of ten (10) minutes. The displacement rate appears to settle to a steady value of about 0.020 nm/s in Al and about 0.009 nm/s in Ni3Al. Such a significant creep effect at the peak load can strongly affect the subsequent unloading behavior, especially when the unloading rate is not high enough.
  • In the extreme case where a creep dominates an elastic recovery at the onset of the unloading process, the load-displacement curve can even exhibit a “nose”, such as shown in FIG. 4 a for an aluminum sample object. Load schedules (i) to (iii), such as those shown in FIG. 3 b, represent three similar indentation experiments on the same aluminum sample. Load schedule (i) has a very rapid unloading rate. Load schedules (ii) and (iii) have the same unloading rate, which is slower than the unloading rate in load schedule (i). On the other hand, load schedules (i) and (ii) have a short load holding period before the unloading process, while load schedule (iii) has a longer load holding period. A conspicuous “nose”, such as that shown in FIG. 4 a , appears in the unloading curve for load schedule (ii). The “nose” disappears when the unloading rate is increased, such as shown in the unloading curve for load schedule (i), or when the load holding period before unloading is lengthened, such as shown in the unloading curve for load schedule (iii).
  • When a “nose” occurs, the elastic modulus cannot be accurately calculated using the Oliver-Pharr scheme, because the apparent contact stiffness Su becomes negative. Moreover, even if a “nose” does not occur, the presence of creep can cause serious errors in the estimation of the elastic modulus, if the creep effect is not corrected. Moreover, creep effects can become significant in certain circumstances, such as where an indentation is performed at a temperature of a significant fraction (e.g., more than 40%) of the absolute melting temperature or where a nano-sized indentation is performed by exerting a very large pressure on the sample.
  • The present invention provides a method for measuring elastic properties, such as the elastic modulus of an object, that avoids the above problems. Moreover, the present invention provides a method for measuring the elastic modulus of a solid material by depth-sensing indentation where the creep effect is corrected. Furthermore, the present invention provides a method for correcting a creep effect occurred when measuring elastic properties of a solid material by depth-sensing indentation.
  • SUMMARY OF THE INVENTION
  • The present invention provides a method for obtaining a correction term for use in correcting a measurement error in measuring a material property. Additionally or alternative, the present invention provides a method for correcting a measurement error in measuring a material property. In one embodiment, the method can correct for the effects of creep occurred in measuring the elastic modulus of various materials by depth-sensing indentation. The method can comprise defining a correction term in the contact compliance between an indenter tip and an object to be measured. In one embodiment, the correction term can be defined by equation (4) below. The method can also comprise quantifying the correction term by measuring the related quantities from the indentation data. In one embodiment, curve fitting can be employed in quantifying the correction term. The creep correction term can be removed from the apparent contact compliance in the calculation of the sample modulus.
  • The present invention can be used to measure a material property. The above correction procedure can be incorporated easily into the analysis software of any existing depth-sensing indentation system based on the Oliver-Pharr scheme.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • These and other features, aspects, and advantages of the invention will become much more apparent from the following description and accompanying drawings, in which:
  • FIGS. 1 a to 1 c show the P-t curve, the h-t curve, and the P-h curve respectively in one embodiment of the invention for modulus measurement using depth-sensing indentation;
  • FIGS. 2 a and 2 b are the displacement-time curves of the load holding process after correction of thermal drift in (a) Al, load=2918.1±1.5 μN and (b) Ni3Al(111), load=4964.6±2.1 μN, respectively;
  • FIGS. 3 a and 3 b show load schedules used in the experiments, in which FIG. 3 b shows the three different load schedules used on a sample material of aluminum;
  • FIG. 4 a is an enlarged view of the unloading portions of the load-displacement curves showing creep effects thereon after correcting thermal drift in aluminum; and FIG. 4 b illustrates the fitting by equation (5) of the unloading curve for Cu(111) with large creep effects, wherein unloading rate=12.47 μN/s, and creep factor C=60.3%; and
  • FIGS. 5 a to 5 c show different modulus-creep factor curves obtained by the Oliver-Pharr scheme and the invention for sample materials of (a) Al, (b) Cu (111), and (c) Ni3Al (111), respectively.
  • DETAILED DESCRIPTION OF THE INVENTION
  • Exemplary methods embodying the principles of the present invention are shown throughout the drawings and described in the various embodiments below.
  • The invention is contemplated to measure various properties of various materials. For example, the invention can measure the elastic properties, such as elastic modulus of a sample material. In the method of the invention, one or more correction term can be obtained and used to correct one or more measurement errors occurred during the measurement of the sample material properties. In one embodiment, a depth-sensing indentation system can be used for measuring the elastic modulus of a sample material. In such an embodiment, the contact stiffness between the depth-sensing indenter and the sample material, after correcting for the effects of creep, can be obtained and used as a corrected term. In another embodiment, one or more corrected terms can be used to obtain the properties, such as the elastic modulus, of the sample material.
  • According to one aspect of the invention, a method is provided to measure elastic properties of various materials using one or more corrected terms. Additionally or alternatively, the method can comprise quantifying the corrected terms.
  • In one embodiment, a method is provided to measure the elastic modulus of a material during the unloading process in depth-sensing indentation. The method can comprise one or more of the following:
      • (a) measuring the indenter displacement drift rate {dot over (h)}h just prior to the unloading process;
      • (b) measuring the apparent contact stiffness Su (the rate of change of load with respect to indenter displacement) at the onset of the unloading process;
      • (c) obtaining the contact stiffness S based on one or more of the indenter displacement drift rate {dot over (h)}h, the apparent contact stiffness Su, and {dot over (P)}, wherein {dot over (P)} is the imposed unloading rate at the onset of the unload process;
      • (d) using the value of S obtained from step (c) to calculate the contact area Ac based on equation (2); and
      • (e) using the value of S obtained from step (c) above and the value of Ac from step (d) above to calculate the reduced modulus Er based on equation (1).
  • According to another aspect of the invention, a method is provided to correct various measurement errors, such as occurred when measuring various properties of a sample material. In an embodiment where a depth-sensing indentation system is used for measuring the elastic properties of a sample material, the method of the invention is capable of correcting various measurement errors, such as caused by creep and/or thermal drift, as will be described in details below.
  • In one embodiment, a method is provided to correct various measurement errors during an unloading process in depth-sensing indentation. The method can comprise one or more of the following:
      • (a) measuring the indenter displacement drift rate {dot over (h)}h just prior to the unloading process;
      • (b) measuring the apparent contact stiffness Su (the rate of change of load with respect to indenter displacement) at the onset of the unloading process; and
      • (c) obtaining a correction term based on one or more of {dot over (h)}h, Su, and {dot over (P)}.
        wherein {dot over (P)} is the imposed unloading rate at the onset of the unload process.
  • In an embodiment where the measurement is carried out by using a depth-sensing indentation system, the correction term can concern the contact stiffness and/or the contact area as will be described in details below.
  • The contact stiffness S can be obtained in various manners. For example, the contact stiffness S can be obtained by taking one or more of the following factors into consideration: the observed (or apparent) contact stiffness Su, the indenter displacement rate {dot over (h)}h, and the unloading rate {dot over (P)}. In an exemplary embodiment, the contact stiffness S to be used in equation (1) can be given by the following equation: 1 S = 1 S n + h . h P . ( 4 )
    wherein the correction term is capable of correcting creep and/or thermal drift. In an exemplary embodiment such as shown in FIG. 1, {dot over (h)}h can be the indenter displacement rate recorded at the end of the load holding period preceding the unloading process. In another exemplary embodiment, {dot over (P)} can be the unloading rate at the onset of the unloading process. In a further exemplary embodiment, Su can be the contact stiffness at the onset of the unloading process. The observed (or apparent) contact stiffness Su, the indenter displacement rate {dot over (h)}h, and/or the unloading rate {dot over (P)} will be described in detail below.
  • In one embodiment, to evaluate the apparent contact stiffness Su at the onset of the unloading process from the unloading portion of the load-displacement P-h curve, the load-displacement P-h curve can be first fitted by the following equation:
    h=h 0 +A 1 P m +A 2 P n   (5)
    wherein h0, A1, A2, m, and n can be fitting constants. For example, h0 can be about 520.55±0.15; A1 can be about 0.254±0.003; A2 can be about 7.7E-23±4.8E-22; m can be about 0.5; and/or n can be about 5.90±0.71. Equation (5) can provide very good fit to the onset portion of the unloading process. In another exemplary embodiment, R2 can be about 0.97785. In one exemplary embodiment, the curve fitting of the load-displacement P-h curve can be carried out during an initial part of the unloading process. In another embodiment, the contact stiffness at the onset of the unloading process can be defined as Su=dP/dh|u, wherein “u” denotes the onset of the unloading process. In an exemplary embodiment, Su can be calculated, such as by differentiating equation (5).
  • In another embodiment, the indenter displacement rate {dot over (h)}h in equation (4) can be obtained by fitting the displacement-time h-t curve during the load holding period or prior to the unloading process by the following empirical law:
    h(t)=h i+β(t−t i)1/3 +Kt   (6)
    where hi, β, ti, and K can be fitting constants. For example, hi can be about 568.66±0.03; β can be about 2.94±0.01, ti can be about 237.32±0.05; and/or K can be about 0.0062±0.0001. Alternatively, hi can be about 184.754±0.022; β can be about 1.320±0.010, ti can be about 274.927±0.096; and/or K can be about 0.00315±0.00009. The above equation is capable of providing very good fittings to the displacement-time h-t curves. In an exemplary embodiment, R2 can be about 0.99753. In another exemplary embodiment, R2 can be about 0.99013. In one embodiment, the indenter displacement rate {dot over (h)}h can be obtained as follows: {dot over (h)}h=dh/dt|h, wherein “h” can denote the end of the load holding period. In a further embodiment, the indenter displacement rate {dot over (h)}h can be obtained by differentiating equation (6). It will be appreciated that various alternate embodiments of calculating the contact stiffness S, the observed (or apparent) contact stiffness Su, the indenter displacement rate {dot over (h)}h, and/or the unloading rate {dot over (P)} are within the scope of the invention.
  • Additionally or alternatively, the correction term can be based in part on the contact depth hc. In an exemplary embodiment, the contact depth hc can be determined from the Oliver-Pharr scheme after thermal drift correction and contact stiffness correction due to creep effects. In another exemplary embodiment, the corrected contact stiffness S obtained from the above equation (4) can be used in equation (2) to obtain a contact depth hc. The corrected contact depth hc can then replace the uncorrected contact depth to obtain the elastic modulus of the sample material as in the Oliver-Pharr scheme. It will be appreciated that various alternate embodiments of obtaining the contact depth hc are within the scope of the invention.
  • The method of the invention will now be described through the various experiments. The invention can be used to measure elastic properties of various materials. In the embodiments such as shown in FIGS. 1 and 2, the following three materials can be used: a single crystal of Ni3Al, a single crystal of copper, and a polycrystalline Al. In an exemplary embodiment, the Ni3Al single crystal can have various compositions. For example, the composition of the Ni3Al single crystal can be of about 75 at. % Ni, about 16.7 at. % Al, about 8.0 at. % Cr, and about 0.3 at. % B. In another exemplary embodiment, the copper single crystal can have a purity of up to 99.99%. In a further exemplary embodiment, the polycrystalline Al can have a grain size of approximately 1 to 2 mm. It will be appreciated that various alternate embodiments of sample materials are within the scope of the invention.
  • Optionally, the sample materials can be subjected to various processes prior to the measurement. In one embodiment, the crystal material can be homogenised prior to nanoindentation. For example, the crystal can be homogenised at about 1250° C. for about 120 hours. In another embodiment, the copper single crystal can be annealed for about 5 hours at about 800° C. In a further embodiment, the polycrystalline Al can be in the as-cast state. It will be appreciated that various alternate embodiments of processing the sample materials are within the scope of the invention.
  • In one embodiment, the indentation surfaces of the various sample objects can be prepared by various methods. For example, the crystal materials can be prepared by having their (111) surface for indentation cut by various means. In an exemplary embodiment, the Ni3Al or the Cu crystal can have its (111) surface for indentation cut such as by a spark machine. Additionally or alternatively, the (111) surface for indentation can be subjected to various processes, such as grinding and electropolishing. In one embodiment, the Al surfaces can be electropolished. It will be appreciated that various alternate embodiments of processing the indentation surfaces of the sample materials are within the scope of the invention.
  • The indentation process can be carried out using various conventional indentation equipment. For example, the indentation process can be carried out with nanoindenters or atomic force microscopy (AFM) setups with a Berkovich tip, such as those manufactured by Hysitron Inc. or TM Microscopes. In one exemplary embodiment, the indentation process can be carried out at room temperature.
  • Various load schedules can be employed in the indentation process. For example, the load schedules can be similar to that as shown in FIG. 3 a or FIG. 3 b. In one embodiment, the load can be ramped up quickly to the peak value. In an exemplary embodiment, the load can reach its peak value within a short period of time, such as within about 50 seconds. The peak value of the load can vary depending on the sample material. For example, the peak value of the load can be from about 3000 μN to about 5000 μN. In one exemplary embodiment, the peak load value for Al can be 2918.1±1.5 μN. In another exemplary embodiment, the peak value for Ni3Al(111) can be 4964.6±2.1 μN.
  • In another embodiment, the load can be held at its peak value for a predetermined period of time. In an exemplary embodiment, the load holding period can be up to about 100 seconds. In another exemplary embodiment, the load holding period can be more than 50 seconds. In a preferred embodiment, the load can be ramped up quickly to the peak value followed by a rapid unloading process. Such a load schedule is capable of initiating the indent shape so that time-independent plasticity can be made negligible in subsequent stages.
  • In a further embodiment, the load can be ramped up again to the peak value after the initial unloading process. In an exemplary embodiment, the load can be held for a load holding period after being ramped up again to the peak value. The contact stiffness S for modulus calculation can be measured from the final unloading process. It will be appreciated that various alternate embodiments of load schedules of the indentation process are within the scope of the invention.
  • Various methods can be adopted to correct the measurement error caused by thermal drift. In one embodiment, low-load holds can be applied to the sample material during the indentation process. In an exemplary embodiment, low-load holds, such as about 15% of the peak load, can be placed towards the end of the final unloading process. In another exemplary embodiment, low-load holds can be placed between the cycles to measure the thermal drift rate. Such low-load holds can be used to assess the fluctuation of the thermal drift rate during the entire measurement. For example, when the thermal drift rate changes beyond a predetermined value during the measurement, the results gathered under such circumstances can be discarded.
  • Creep effects can have significant impact on the modulus measured. For example, the following creep factor C can be used to represent the importance of creep over elasticity: C = h . h c S P . ( 7 )
    wherein {dot over (h)}h c is the creep portion of {dot over (h)}h. In an exemplary embodiment, {dot over (h)}h c can be obtained by subtracting the thermal drift rate from {dot over (h)}h . According to equation (7), a large creep factor C can result from a slow unloading rate and/or a short load holding period, which can cause a high creep displacement rate at the end of the load holding period.
  • FIG. 4 b shows a “nose” occurrence in the load-displacement P-h curve during an unloading process in Cu. The indentation conditions can be such that the creep factor defined in equation (7) can be about 60% so that the creep effect is significant. According to one embodiment of the invention, equation (5) can provide very good fit to the onset portion of the unloading process. In an exemplary embodiment, the value of Su fitted by equation (5) can be about 3454 μN/nm. In another exemplary embodiment, R2=0.97785.
  • FIGS. 5 a to 5 c show modulus-creep factor E-C curves containing modulus data measured from three sample materials. The creep factors C in FIGS. 5 a to 5 c can be defined by equation (7). All modulus results shown in FIGS. 5 a to 5 c, whether corrected for creep or not, have been corrected for thermal drift and machine compliance. As shown in FIGS. 5 a to 5 c, modulus values obtained without correcting for the effects of creep increase when the creep factor C increases. For example, the apparent modulus for Al and Cu is dramatically high, such as over 2000 GPa, when the creep factor C is higher than about 1.4.
  • FIGS. 5 a to 5 c also show the modulus values obtained based on equations (1) and (2) wherein the contact stiffness S is corrected by equation (4). After the creep effect is corrected by equation (4), the calculated modulus values tend towards a constant value. According to one embodiment, the corrected modulus is about 72.3±7.5 GPa for Al, about 116.9±11.1 GPa for Cu, and about 189.9±11.9 GPa for Ni3Al. The theoretical values of the reduced modulus calculated using the method of Vlassak and Nix are 74.8 GPa for polycrystalline Al, 125.9 GPa for Cu( 111), and 201.9 GPa for Ni3Al(111). Such theoretical values of the reduced modulus all fall within the corresponding modulus value ranges measured by the method of the invention.
  • It will be appreciated that the various features described herein may be used singly or in any combination thereof. Therefore, the present invention is not limited to only the embodiments specifically described herein. While the foregoing description and drawings represent a preferred embodiment of the present invention, it will be understood that various additions, modifications, and substitutions may be made therein without departing from the spirit and scope of the present invention. In particular, it will be clear to those skilled in the art that the present invention may be embodied in other specific forms, structures, arrangements, proportions, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. One skilled in the art will appreciate that the invention may be used with many modifications of structure, arrangement, proportions, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. The presently disclosed embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being not limited to the foregoing description.

Claims (20)

  1. 1. A method for measuring a material property, comprising:
    obtaining a correction term; and
    determining the material property using the correction term;
    wherein the correction term reduces a measurement error occurred during the measurement of the material property.
  2. 2. The method of claim 1, wherein the correction term comprises one or more of the following: a contact stiffness, a contact area, and a contact depth.
  3. 3. The method of claim 1, wherein the correction term comprises a contact stiffness S.
  4. 4. The method of claim 1, wherein the correction term is based on one or more of the indenter displacement drift rate {dot over (h)}h, the apparent contact stiffness Su, and {dot over (P)}; wherein:
    the indenter displacement drift rate {dot over (h)}h is measured prior to the unload process;
    the apparent contact stiffness Su is measured at the onset of the unloading process; and
    {dot over (P)} is the imposed unloading rate at the onset of the unload process.
  5. 5. The method of claim 4, wherein the correction term comprises a contact stiffness S determined by the following equation:
    1 S = 1 S u + h . h P . .
  6. 6. The method of claim 5, wherein the correction term further comprises a contact depth hc determined as follows:
    h c = h max - ɛ P max S
    wherein hmax is the maximum indenter displacement, Pmax is the maximum load imposed, and ε is a constant.
  7. 7. The method of claim 5, wherein the correction term is a contact area Ac determined as follows:
    A c = f ( h c ) , h c = h max - ɛ P max S
    wherein hc is a contact depth, hmax is the maximum indenter displacement, Pmax is the maximum load imposed, and ε is a constant.
  8. 8. The method of claim 7, wherein the material property obtained is a reduced modulus Er determined by the following equation:
    E r = π 2 S A c
  9. 9. The method of claim 1, wherein a crystal material is measured.
  10. 10. The method of claim 9, wherein the crystal material comprises one of the following: a single crystal of Ni3Al, a single crystal of copper, or a polycrystalline Al.
  11. 11. A method for correcting a measurement error in measuring a material property during an unloading process in the depth-sensing indentation, comprising:
    obtaining a correction term based on one or more of the indenter displacement drift rate {dot over (h)}h, the apparent contact stiffness Su, and {dot over (P)}; and
    correcting the measurement error using the correction term;
    wherein the indenter displacement drift rate {dot over (h)}h is measured prior to the unloading process; the apparent contact stiffness Su is measured at the onset of the unloading process; and {dot over (P)} is the imposed unloading rate at the onset of the unload process.
  12. 12. The method of claim 11, wherein the correction term comprises a contact stiffness S.
  13. 13. The method of claim 12, wherein the contact stiffness S is determined according to the following equation:
    1 S = 1 S u + h . h P . .
  14. 14. The method of claim 11, wherein the correction term comprises a contact depth hc based on the following:
    h c = h max - ɛ P max ( 1 S u + h . h P . )
    wherein hmax is the maximum indenter displacement, Pmax is the maximum load imposed, ε is a constant.
  15. 15. The method of claim 11, wherein the correction term comprises a contact area Ac determined as follows:
    A c = f ( h c ) , h c = h max - ɛ P max ( 1 S u + h . h P . )
    wherein hc is a contact depth, hmax is the maximum indenter displacement, Pmax is the maximum load imposed, and ε is a constant.
  16. 16. The method of claim 11, wherein the indenter displacement drift rate {dot over (h)}h is obtained by curve fitting of the data of indenter displacement-time h-t curve prior to the unloading process by the following equation:

    h(t)=h i+β(t−t i)1/3 +Kt
    wherein hi, β, ti, and K are fitting constants.
  17. 17. The method of claim 11, wherein the indenter displacement drift rate {dot over (h)}h is obtained by differentiating the following equation:

    h(t)=h i+β(t−t i)1/3 +Kt
    wherein hi, β, ti, and K are fitting constants.
  18. 18. The method of claim 11, wherein the indenter displacement drift rate {dot over (h)}h is obtained by the following equation:

    {dot over (h)} h =dh/dt| h
    wherein h denotes the end of the load holding period.
  19. 19. The method of claim 11, wherein the apparent contact stiffness Su is obtained by curve fitting of the data of load-indenter displacement P-h curve during an initial part of the unloading process by the following equation:

    h=h o ±A 1 P m +A 2 P n
    wherein ho, A1, A2, m, and n are fitting constants.
  20. 20. The method of claim 11, further comprising obtaining a second correction term, wherein the second correction term is based in part on one or more of the following: the maximum indenter displacement, the indenter geometry, the contact depth, the maximum load imposed, the apparent contact stiffness measured at the onset of the unloading process, the indenter displacement drift rate measured prior to the unloading process, and the imposed unloading rate measured at the onset of the unloading process.
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Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6993959B2 (en) * 2003-10-17 2006-02-07 National Institutes Of Health System and method for the analysis of atomic force microscopy data
JP4320018B2 (en) * 2006-01-06 2009-08-26 国立大学法人広島大学 Micro-hardness measurement method and micro hardness tester
JP2008215940A (en) * 2007-03-01 2008-09-18 Canon Inc Foreign matter inspection device and foreign matter inspection method using the same
US8265884B2 (en) * 2008-07-29 2012-09-11 President And Fellows Of Harvard College Method to measure the elastic modulus and hardness of thin film on substrate by nanoindentation
US8256086B2 (en) * 2009-06-25 2012-09-04 Lockheed Martin Corporation Method of producing missile nose cones
US8322217B2 (en) 2010-04-06 2012-12-04 Varel Europe S.A.S. Acoustic emission toughness testing for PDC, PCBN, or other hard or superhard material inserts
US8365599B2 (en) 2010-04-06 2013-02-05 Varel Europe S.A.S. Acoustic emission toughness testing for PDC, PCBN, or other hard or superhard materials
US8596124B2 (en) 2010-04-06 2013-12-03 Varel International Ind., L.P. Acoustic emission toughness testing having smaller noise ratio
US9297731B2 (en) 2010-04-06 2016-03-29 Varel Europe S.A.S Acoustic emission toughness testing for PDC, PCBN, or other hard or superhard material inserts
US9086348B2 (en) 2010-04-06 2015-07-21 Varel Europe S.A.S. Downhole acoustic emission formation sampling
US8397572B2 (en) 2010-04-06 2013-03-19 Varel Europe S.A.S. Acoustic emission toughness testing for PDC, PCBN, or other hard or superhard materials
CN101806690B (en) * 2010-05-04 2011-07-20 中国地质大学(北京) Method for testing physical performances of film and film-substrate interface based on nanometer indentation continuous stiffness curve
US20130247645A1 (en) * 2012-03-26 2013-09-26 Matsuzawa Co., Ltd. Hardness tester and hardness testing method
US9249059B2 (en) 2012-04-05 2016-02-02 Varel International Ind., L.P. High temperature high heating rate treatment of PDC cutters
EP2679778A1 (en) * 2012-06-27 2014-01-01 Alstom Technology Ltd A method for measuring geometry deformations of a turbine component
CN103913385A (en) * 2014-04-02 2014-07-09 西安交通大学 Comprehensive experiment table for measuring normal and tangential contact rigidity of mechanical junction surface
GB2540821B (en) * 2015-07-30 2018-07-04 Univ Of Central Lancashire Apparatus and system for measuring mechanical properties of materials using depth sensing indentation

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3969928A (en) * 1973-06-26 1976-07-20 Skf Compagnie D'applications Mecaniques Non-destructive testing method for determining a body's mechanical properties and stresses
US4699000A (en) * 1986-04-17 1987-10-13 Micro Properties Inc. Automated device for determining and evaluating the mechanical properties of materials
US4848141A (en) * 1988-04-06 1989-07-18 Oliver Warren C Method for continuous determination of the elastic stiffness of contact between two bodies
US5067346A (en) * 1986-07-10 1991-11-26 Commonwealth Scientific And Industrial Research Organization Penetrating measuring instrument
US5133210A (en) * 1990-02-06 1992-07-28 The University Of Maryland Thermal expansion driven indentation stress-strain system
US5320800A (en) * 1989-12-05 1994-06-14 Arch Development Corporation Nanocrystalline ceramic materials
US5904658A (en) * 1996-08-23 1999-05-18 Osteobiologics, Inc. Hand-held materials tester
US5999887A (en) * 1997-02-26 1999-12-07 Massachusetts Institute Of Technology Method and apparatus for determination of mechanical properties of functionally-graded materials
US6053034A (en) * 1998-10-09 2000-04-25 Advanced Micro Devices, Inc. Method for measuring fracture toughness of thin films
US6134954A (en) * 1996-04-15 2000-10-24 Massachusetts Institute Of Technology Depth sensing indentation and methodology for mechanical property measurements
US6311135B1 (en) * 1998-05-26 2001-10-30 Inventium Llc Method and apparatus for determining preexisting stresses based on indentation or other mechanical probing of the material
US20030060987A1 (en) * 2001-03-07 2003-03-27 Ming Dao Systems and methods for estimation and analysis of mechanical property data associated with indentation testing
US20030099495A1 (en) * 2001-11-05 2003-05-29 3M Innovative Properties Company Method of printing film and articles
US6641893B1 (en) * 1997-03-14 2003-11-04 Massachusetts Institute Of Technology Functionally-graded materials and the engineering of tribological resistance at surfaces

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3969928A (en) * 1973-06-26 1976-07-20 Skf Compagnie D'applications Mecaniques Non-destructive testing method for determining a body's mechanical properties and stresses
US4699000A (en) * 1986-04-17 1987-10-13 Micro Properties Inc. Automated device for determining and evaluating the mechanical properties of materials
US5067346A (en) * 1986-07-10 1991-11-26 Commonwealth Scientific And Industrial Research Organization Penetrating measuring instrument
US4848141A (en) * 1988-04-06 1989-07-18 Oliver Warren C Method for continuous determination of the elastic stiffness of contact between two bodies
US5320800A (en) * 1989-12-05 1994-06-14 Arch Development Corporation Nanocrystalline ceramic materials
US5133210A (en) * 1990-02-06 1992-07-28 The University Of Maryland Thermal expansion driven indentation stress-strain system
US6134954A (en) * 1996-04-15 2000-10-24 Massachusetts Institute Of Technology Depth sensing indentation and methodology for mechanical property measurements
US6247355B1 (en) * 1996-04-15 2001-06-19 Massachusetts Institute Of Technology Depth sensing indentation and methodology for mechanical property measurements
US5904658A (en) * 1996-08-23 1999-05-18 Osteobiologics, Inc. Hand-held materials tester
US5999887A (en) * 1997-02-26 1999-12-07 Massachusetts Institute Of Technology Method and apparatus for determination of mechanical properties of functionally-graded materials
US6641893B1 (en) * 1997-03-14 2003-11-04 Massachusetts Institute Of Technology Functionally-graded materials and the engineering of tribological resistance at surfaces
US6311135B1 (en) * 1998-05-26 2001-10-30 Inventium Llc Method and apparatus for determining preexisting stresses based on indentation or other mechanical probing of the material
US6053034A (en) * 1998-10-09 2000-04-25 Advanced Micro Devices, Inc. Method for measuring fracture toughness of thin films
US20030060987A1 (en) * 2001-03-07 2003-03-27 Ming Dao Systems and methods for estimation and analysis of mechanical property data associated with indentation testing
US20030099495A1 (en) * 2001-11-05 2003-05-29 3M Innovative Properties Company Method of printing film and articles

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