Most of the materials and their property data can be found in following references-
1. ASM Handbooks
2. Atlas of stress-strain curves
3. Graphical stress-strain plot using available end points
4. Ramberg-Osgood Equation
5. ASME Sec VIII Div 2-ANNEX 3.F/ASME Sec II Part D for equations or similar properties at high temperature
6. Matweb.com
7. API 579
8. asm.matweb.com
9. Google