Yes,
Basically the material file is an xml v1.0 type file but it is saved under the extension ".sldmat"
the file is located under the ...Solidworks/Lang/English folder and its called "SolidWorks Materials.sldmat"
You can edit the contents of it by using notepad even. The file is structured like this:
<Material Class> (for instance "STEEL"

-------<name of material> (Like SAE 1010)
-----------material information (Material Properties)
-------<end material>
-------<next material name>(Like SAE 1040)
-----------material information (Material Properties)
-------<end material>
<end of class>
Here is a sample of two of the materials listed in the file:
<classification name="Steel">
<material name="AISI 304">
<shaders>
<pwshader name="stainless steel"/> <!-- OK -->
<cgshader name="SteelAISI304"/>
<swtexture path="images\textures\metal\cast\cast_fine.jpg"/>
</shaders>
<swatchcolor RGB="9DA4AC">
<sldcolorswatch:Optical Ambient='0.520000' Transparency='0.000000' Diffuse='0.800000' Specularity='1.000000' Shininess='0.400000' Emission='0.000000'/>
</swatchcolor>
<xhatch name="ANSI32 (Steel)" angle="0.0" scale="1.0"/>
<physicalproperties>
<EX displayname="Elastic Modulus" value="0.19E+12"/>
<NUXY displayname="Poissons Ratio" value="0.29"/>
<GXY displayname="Shear Modulus" value="0.75E+11"/>
<ALPX displayname="Thermal Expansion Coefficient" value="0.18E-4"/>
<DENS displayname="Density" value="0.80E+04"/>
<KX displayname="Thermal Conductivity" value="16."/>
<C displayname="Specific Heat" value="0.50E+03"/>
<SIGXT displayname="Tensile Strength" value="5.17017E+8"/>
<SIGYLD displayname="Yield Strength" value="2.06807E+8"/>
</physicalproperties>
</material>
<material name="AISI 1020">
<shaders>
<pwshader name="stainless steel"/> <!-- OK -->
<cgshader name="SteelAISI1020"/>
<swtexture path="images\textures\metal\cast\cast_fine.jpg"/>
</shaders>
<swatchcolor RGB="C6C6D1">
<sldcolorswatch:Optical Ambient='0.520000' Transparency='0.000000' Diffuse='0.800000' Specularity='1.000000' Shininess='0.400000' Emission='0.000000'/>
</swatchcolor>
<xhatch name="ANSI32 (Steel)" angle="0.0" scale="1.0"/>
<physicalproperties>
<EX displayname="Elastic Modulus" value="0.20E+12"/>
<NUXY displayname="Poissons Ratio" value="0.29"/>
<GXY displayname="Shear Modulus" value="0.77E+11"/>
<ALPX displayname="Thermal Expansion Coefficient" value="0.15E-4"/>
<DENS displayname="Density" value="0.79E+04"/>
<KX displayname="Thermal Conductivity" value="47."/>
<C displayname="Specific Heat" value="0.42E+03"/>
<SIGXT displayname="Tensile Strength" value="4.20507E+8"/>
<SIGYLD displayname="Yield Strength" value="3.51571E+8"/>
</physicalproperties>
</material>
You can build this yourself in notepad if you like or whatever method you prefer. Whatever you do, do not modify the original... copy or create a new one. place it in the same folder with the original file and you will see it available the next time you use the material editor.
hope that helps
Regards,
Jon
jgbena@yahoo.com