README for Material Property Database (MPDB)

• Program details
  
• Notes on the material properties
  
• Notes for SOLIDWORKS users
  
• Notes for Abaqus users
  
• Notes on user materials
  
• Installation notes for network/site licenses (Windows only)
  
• FAQ's
  
  
  
  
  

Program Details

1. Both versions (Windows and Linux) have the same data and the same functionality.
   
   
2. The demo version is fully functional. However, the property values for non-elements are multiplied by a random number and should not be used. Also, the references are not shown for the non-elements. The data for the elements are provided for free.
   
   
3. Single-clicking on an element or double-clicking on a material will bring up a form showing the properties that are available for that material.
   
   
4. Right clicking on an element will bring up a window listing all of the materials in the database that have that element as a major component. A material can then be selected from this list by left clicking on it. A right mouse click will dismiss this window.
   
   
5. The menu item "Materials->List materials by UNS number..." will bring up a window listing the materials in the database by their UNS number (if they have one). A material can then be selected from this list by left clicking on it. A right mouse click will dismiss this window.
   
   
6. Select the property, phase, orientation (if available) and output format.
   
   
7. The data can also be written directly to a text file.
   
   
8. The directory where the text file will be written can be changed with the "Options->Output..." menu item.
   
   
9. The output units of the properties can be changed with the "Options->Units..." menu item.
   
   
10. The vapor pressure can be written out as log(pressure) or as the pressure itself. This can be selected in the "Options->Output..." menu.
    
    
11. The subroutines/functions return either a default value or the last valid value when the requested temperature is out of the range of the data. The default value is preset to 1.0E100. The return value can be changed in the "Options->Output..." menu.
    
    
12. Two types of search options are available under the "Materials->Search/Report Values" menu item. The user goes to the material class they are interested in (Ni based alloys for example) and then selects the "Search/Report" menu item. "Report" will return the desired property at a user specified temperature for all of the materials in the current class. "Search" allows the user to specify the desired temperature and a minimum and maximum value for a property and returns all materials that match. If you leave either the minimum or maximum value blank this limit will be ignored, this is the same as entering a very small or a very large value for the limit. If the "search all materials" option is selected the entire database will be searched. You can place the cursor on the line of a material and click the "Goto" button to go this material in the main program. More than one property can be selected at a time. If the "optional" box is checked for a property, then the material is included in the results even if this property is missing from the database.
    
    
13. The experimental data were fit to an equation to give the best numerical values. The mathematic forms used do not imply any physical model. It is not recommended that derivatives be taken of these equations without examination of the resultant values.
    
    
14. Some of the equations are too long to fit into Excel, and only part of the equation will be pasted into Excel which results in an Excel error. No fix for this problem is known.
    
    
15. All compositions given are nominal values only.
    
    
16. A listing of all of the materials and the properties for each of the materials can be written to a file with the menu item "Options->Write materials file". The file is called materials_and_data.txt and is an ASCII text file. This file is written to the directory where the text file with the data/subroutines are written.
    
    
17. Users can add their own properties to the database.
    
    You can select to use either a local user_mats.txt file or a remote one. The local user_mats.txt file will reside in the directory where the program is. The remote user_mats.txt file will be in another directory or on another machine over the network.
    
    You can only add or change materials if you have selected "User materials->Use local user_mats.txt file". This allows multiple users to have one central user_mats.txt which is administered by one person.
    
    The "User materials" tab must be selected, the menu items for adding/editing/deleting user materials are then active. Select the "Add new material..." option and enter your data.
    
    The data can be entered as one of five types of equation. For all but the "single point data" or "x-y pairs" format the temperatures must be in Kelvin and the data itself must be in the proper units - these are indicated in the window. For the "single point data" or "x-y pairs" format (the exact name depends on the version you are using) you can select the units that you enter the data in. Once the data is entered you can select any units as usual. If you enter your data in the "single point data" or "x-y pairs" format the program will fit a straight line between the data points.
    
    To remove the data for a property for a given material, without deleting the entire material, change the "Number of temperature zones" for that property to 0 or click the "clear current dataset" button and then the "Save dataset" button.
    
    You can add more than one set of data for a given property by specifying a "Phase/Condition" and "Orientation/Condition". You can change the default name of a "Phase/Condition" or "Orientation/Condition" by right clicking on the label. You must specify a "Phase/Condition", but you do not have to select an "Orientation/Condition" unless you want to add more than one dataset. The actual "Phase/Condition" or "Orientation/Condition" is only used to organize your data and does not have any other significance.
    
    After adding or editing data you must click the "Save data" set button. After all of your changes are made, click the "OK" button to save your changes to disk. All of your user material data is written to a file called "user_mats.txt" in the directory where your application is, usually c:\program files\MPDB\. You may want to periodically make copies of this file as a back-up. All versions of the program use the same format for the user_mats.txt file so it can be shared among them.
    
    
18. The data can be plotted within the program.
    
    Once the plot is displayed the axis can be formatted to a limited extend. Use the menu item "Plot Options->Axis options..." to do this.
    
    You can display the point values by clicking in the plot if this option is enabled in the "Plot Options" menu. The x and y values are reported in the menu bar. The mouse wheel can be scrolled to move the point being read. If you hold down the shift key while scrolling the point will move faster.
    
    
19. Larson-Miller equations can be manipulated.
    
    Larson-Miller equations were fitted to the stress-rupture and creep strength data for some materials. When you select a "Master curve (LMP)" dataset a button will be enabled. Clicking the button will open a new window where you can manipulate the LM equations to make a plot or a listing of the values as functions of time or temperature. There is a "Help" listing available on that window with more details.
    
    

Notes on the material properties:

• Linear expansion (ΔL/L): This property is fairly insensitive to composition and heat treatment. Notable exceptions are the "zero-expansion" Invar type alloys (Fe-36Ni).
  
  
• Coefficient of thermal expansion (CTE): This property is also fairly insensitive to composition and heat treatment. Notable exceptions are the "zero-expansion" Invar type alloys (Fe-36Ni). The value given in the database is the instantaneous thermal expansion; the derivative of (ΔL/L) with respect to the temperature, ∂(ΔL/L)/∂T.
  
  
• Mean coefficient of thermal expansion (MTE): This property is also fairly insensitive to composition and heat treatment. Notable exceptions are the "zero-expansion" Invar type alloys (Fe-36Ni). This value is defined as ΔL/L_T / (T-T_ref). In most cases this property is calculated from the ΔL/L values. The error is expected to be in the range of 10% to 15%, it may be higher near room temperature due to the small value of T-T_ref.
  
  
• ΔL/L, MTE and CTE for filled polymers: In some cases, data is given for both the flow direction and the cross-flow direction. A "weighted average" value is calculated to represent the expansion for the cases where the directionality is not strong, or the software cannot handle the directional values. it is calculated as:
  
  MTE _WA = (MTE _flow + 2 * MTE_cross-flow)) / 3.
  
  
• Elastic & shear modulus: These properties are fairly insensitive to composition and heat treatment. Order-disorder transformations may cause anomalous behavior. Strongly anisotropic materials may have a texture effect. Some Fe-Ni alloys are sensitive to the amount of cold work. The accuracy of this data is estimated to be approximately 5% to 10%. For solder alloys the literature reports a wide spread of values. Data from several sources, when available, are evaluated and representative values are given, the error is estimated to be 10% to 25%. For some polymers the flexural modulus is used as the elastic modulus. The flexural modulus is typically within 10% of the elastic modulus. Typically, values measured with a strain gauge are approximately 10% lower than those measured with a dynamic technique. Values measured by a dynamic technique are preferred over those measured by strain gauge techniques.
  
  Note: for cubic materials where the elastic and shear modulus were calculated from the elastic constants (C₁₁, C₁₂, C₄₄) the average of the Reuss and Voigt equations were used (see R.F.S. Hearmon, Advanced Physics, v5, p232 (1956)). For isotropic solids (glasses) L.D. Landau and E.M. Sifshitz, in Theory of Elasticity, Pub. Addison-Wesley, New York (1966) was used.
  
  
• Poisson's ratio & bulk modulus: These properties are calculated from the elastic & shear modulus using standard relationships and in this sense are self-consistent and accurate. The accuracy of this data is estimated to be approximately 10% to 20%, however since this is a derived quantity the error can be significantly higher. The curves for these properties often show improbable shapes which are most likely due to their derived nature and are not believed to be real. If the elastic & shear modulus were determined in a self-consistent manner the curves would likely be much better behaved. However, all of the data are presented "as is" from the original references and are self-consistent within this database.
  
  
• Thermal conductivity: This property is very sensitive to impurities, heat treatment and mechanical worked state, especially at very low temperatures. This sensitivity is somewhat decreased above room temperature and decreases as the amount of alloying increases. Compare 4340-QT (quenched and tempered) and 4340-NT (annealed).
  
  
• Viscosity: This property is fairly insensitive to composition except for glasses where the sensitivity can be large.
  
  
• Surface tension: There is significant variation between sources for some materials. This property is very sensitive to the atmosphere and to surface active impurities. The atmosphere is typically a non-reactive gas or vacuum, although it is frequently not specified. For the organic liquids it is usually a non-reactive gas (N₂, air, Ar) or the vapor of the liquid being tested. For metals it is usually a vacuum.
  
  
• Specific heat (C_p - constant pressure): This property is fairly insensitive to composition and heat treatment.
  
  
• Heat capacity: This property is fairly insensitive to composition and heat treatment.
  
  
• Vapor pressure: This property can be strongly affected by the presence of trace gases, such as oxygen.
  
  
• Thermal diffusivity: This property is also very sensitive to impurities, heat treatment and mechanical worked state, especially at very low temperatures. This sensitivity is somewhat decreased above room temperature and decreases as the amount of alloying increases. An example of this can be seen by comparing the data for elemental (high purity) Fe and Armco iron (commercial purity).
  
  
• Electrical resistivity: This property is also very sensitive to impurities, heat treatment and mechanical worked state, especially at very low temperatures. This sensitivity is decreased above room temperature.
  
  
• Hemispherical total emissivity (ε_T): the measured emissivity over all wavelengths and 2π radians. This is the emissivity used in the Stefan-Boltzmann law.
  
  
• Normal total emissivity (ε_T,n): the measured emissivity over all wavelengths at a direction normal to the surface. This is the most commonly reported value. For polished metal the following assumption is valid: ε_T/ε_T,n = 1.15 to 1.20.
  
  
• Both emissivities are sensitive to the surface condition (roughness and oxide thickness).
  
  
• Density (ρ): The density for solids is calculated from the room temperature density and the linear expansion coefficient and is calculated as ρ(T) = ρ(RT) / (1 + (ΔL/L))³. The data for oxides, carbides and nitrides depend on the porosity of the material. For gases the ideal gas law is used.
  
  
• Tensile strength, yield strength and elongation: Most of the data for these properties are taken from product brochures provided by the material suppliers. These data should be used with the understanding that they are only representative of the actual material properties. The variation with temperature is usually not smooth. The tensile and yield strengths depend on (grain size)^-1/2 of the materials, however, the grain size is usually not given in the reference. Many of these materials are precipitation hardening alloys and the temperature affects the aging processes different ways at different temperatures. Unless otherwise stated, the data are for "short" times at the indicated temperatures and not for the equilibrium structure. These properties are very sensitive to the details of the processing and heat treatments. Comparison of data from different suppliers indicate that the spread in the published values is approximately 20% for materials with similar processing. The spread in the elongation data can be as high as 50% to 100%.
  
  
• Flexural strength and flexural modulus: This data is for engineering plastic materials. Most of the data for these properties are taken from product brochures provided by the material suppliers. These data should be used with the understanding that they are only representative of the actual material properties. These properties are affected by the moisture content of the test material. Filled materials are also affected fiber/particle orientation and size and by the mold filling process. Different manufacturers use different proprietary additives and similar materials from different suppliers may have different properties and/or temperature dependencies. Comparison of data from different suppliers for similar materials indicate that the spread in the published values is approximately 15% for the flexural modulus and 20% for the flexural strength.
  
  
• Apparent viscosity: Most of the data for the engineering plastics are taken from product brochures provided by the material suppliers. These data should be used with the understanding that they are only representative of the actual material properties. The uncertainty in the values is unknown.
  
  
• True stress-true strain curves: Most of this data was measured at room temperature. The curves in the database are for the true plastic strain. Data for engineering stress-strain curves are not included since finite element programs require the true stress-strain and not the engineering values. The differences between the true values and engineering values can be quite significant. The plastic strain for all of the curves was calculated using the 0.2% offset method if it was not calculated in the reference. Since there is a limited amount of this data, difference sources for the same data cannot be found. The error (spread) is therefore assumed to be similar to that suggested above for the yield strength. The error will be larger near 0 strain due to difficulties in defining the 0.2% offset stress. For some datasets (as noted in the database) engineering stress-strain data in tension have been converted into true stress-strain curves using the equation below:
  
  σ_true = σ_eng(1 + ε_eng)      and      ε_true = ln(1 + ε_eng)
  where σ_true is the true stress, σ_eng is the engineering stress, ε_true is the plastic true strain, ε_eng is the total engineering strain. This equation is valid up to the onset of necking. In compression the conversion is as follows:
  
  σ_true = σ_eng(1 - ε_eng)      and      ε_true = ln(1/(1 - ε_eng))
  
  
• Engineering stress-true strain curves: This data for engineering plastics are taken from product brochures provided by the material suppliers. These data should be used with the understanding that they are only representative of the actual material properties. Typically, unreinforced materials are measured at a cross-head speed of 50 mm/min in tension, reinforced materials are measured at 5 mm/min in tension. The uncertainty in the values is unknown.
  
  
• Creep strength and Stress-rupture curves: This data is very sensitive to the microstructure, heat treatment and test atmosphere. There is usually a large amount of scatter in type of data.
  
  
• 1. For some materials a "master curve" is given for the stress-rupture and creep strength data. This curve is the rupture stress or creep strength vs. the Larson-Miller Parameter (LMP), where the LMP is given by:
     
     LPM = (T, K) * [C + log₁₀(t, hr)] / 1000
     
     where T is the temperature in Kelvin, C is a constant and t is the rupture time in hours.
     
     
     
  2. Note that in the database the LMP divided by 1000 is used in the equations. The LMP must be calculated in Kelvin and hours regardless of the units the user has selected in the program. The stress will be reported in which ever units the user has selected.
     
     
     
  3. The value of the constant C is reported in the material note.
     
     
     
  4. The temperature range over which the master curve is valid is also reported in the material note. You should be very cautious if you extrapolate outside of this temperature range. At higher temperatures the microstructure of the material can change which could significantly affect the stress-rupture behavior.
     
     
     
  5. In some cases the creep strength is calculated from the minimum creep rate. In these cases the stress values may exceed the stress-rupture value and are only indicative of the general creep behavior.
     
     
     
• Isochronous creep curves: For metals, this data is usually calculated from the Larson-Miller (master curve) fit of the creep strength and the strain is the plastic strain, the elastic strain is not included. For plastics the strain is usually the total strain (elastic plus plastic). See the note for the individual material for more details.
  
  
1. In some cases the creep curves are calculated from the minimum creep rate. In these cases the stress values may exceed the stress-rupture value and are only indicative of the general creep behavior.
   
   
   
• Magnetic properties (B vs H, H vs B and permeability vs H): This data is also very sensitive to the microstructure and heat treatment. All of this data is derived from the B vs H data. B is defined as the magnetic flux density and H is defined as the magnetic field intensity. The absolute permeability, μ, is defined as B/H. The relative permeability, μ_r, is unitless and is defined by:
  
  μ_r = μ / μ₀
  
  where μ₀ is the permeability of a vacuum and equals 4π x 10^-7.
  
  The error range for this type of data are not given in any of the references but it is estimated to be in the range of 10% to 20% especially at the lower values.
  
  
• Core loss and exciting power versus magnetic flux density (B): This data is given at different frequencies. The error for this type of data is not given in any of the references but it is estimated to be in the range of 10% to 20% and is likely higher at the lower values of B.
  
  
• Relative permittivity (dielectric constant): The data is typically only given at a limited number of frequencies, i.e., 10³, 10⁶, 10⁹ Hz, the values between these points are interpolated using a semi-log relationship and the accuracy is unknown over the interpolated range. The data is usually reported as being measured in accordance with ASTM D 150, ASTM D 2520 B or IEC 60250. A limited number of datasets have values for the same sample measured with the different standards. Those from IEC 60250 are typically 10% higher than those from ASTM D 2520 B.
  
  
• Dissipation factor: The data is typically only given at a limited number of frequencies, i.e., 10³, 10⁶, 10⁹ Hz, the values between these points are interpolated using a ln-ln relationship and the accuracy is unknown over the interpolated range. The data is usually reported as being measured in accordance with ASTM D 150, ASTM D 2520 B or IEC 60250. A limited number of datasets have values for the same sample measured with the different standards. Those from IEC 60250 are typically 10% to 30% higher higher than those from ASTM D 2520 B.
  
  
• Refractive index: Most of this data is for glasses and polycarbonates. The refractive index is sensitive to the cooling rate and stress state (annealing state) of the material.
  
  


• The properties of polymers and polymer-based composites are sensitive to moisture, processing conditions and may show time-dependence at the higher temperatures. The errors/uncertainties can be large compared to those of other materials. You should use the properties of these materials with this in mind.
  
  
• The glass transition temperature (T_g) for polymers and glasses is an approximate value. There are several methods to determine the T_g and they all give slightly different values. The data in the region of T_g will have a larger variability and uncertainty than at other temperatures. This should be kept in mind if you are doing calculations in the region of T_g.
  
  
• The magnitude of the errors reported by authors for a given property is usually smaller by a factor of 2 to 3 than the error between difference sources for the same data. This is especially true for materials such as ceramics.