What Brian says is true, but the example he gave is in the OLD format. The NEW format, you don't want to edit with a text editor, and the material file works with Pro/E and Mechanica. Here's an example of the new format.
ND_RelParSet_K01 = {
Name = Alum_6061-T6_SI
PARAMETERS =
{
Name = PTC_MATERIAL_DESCRIPTION
Type = String
Default = 'AL 6061-T6 - LLNL Engr. Design Safety Standards Ch. F Rev2'
Access = Locked
},
{
Name = TEMPERATURE
Type = Real
Default = 2.000E+01 C
Access = Full
},
{
Name = PTC_MASS_DENSITY
Type = Real
Default = 2.710000E+03 kg/m^3
Access = Locked
},
{
Name = PTC_THERMAL_EXPANSION_COEF
Type = Real
Default = 2.3580E-05 /K
Access = Locked
},
{
Name = PTC_THERMAL_CONDUCTIVITY
Type = Real
Default = 1.80E+02 N/(sec K)
Access = Locked
},
{
Name = PTC_SPECIFIC_HEAT
Type = Real
Default = 9.6300E+02 m^2/(sec^2 K)
Access = Locked
},
{
Name = PTC_YOUNG_MODULUS
Type = Real
Default = 6.89000E+04 MPa
Access = Locked
},
{
Name = PTC_POISSON_RATIO
Type = Real
Default = 3.300000E-01
Access = Locked
},
{
Name = PTC_TENSILE_YIELD_STRESS
Type = Real
Default = 2.41000E+02 MPa
Access = Locked
},
{
Name = PTC_TENSILE_ULTIMATE_STRESS
Type = Real
Default = 2.90000E+02 MPa
Access = Locked
},
{
Name = PTC_XHATCH_FILE
Type = String
Default = 'aluminum'
Access = Full
},
{
Name = COMMON_NAME
Type = String
Default = 'AL 6061-T6'
Access = Locked
}
}