2. Introduction
• Mechanical Properties of regular engineering
materials are affected by change in Temperature.
• Special High Temperature materials are used for
high temperature working conditions.
3. Properties of High temperature Materials
• High temperature resistance
• High oxidation and corrosion resistance
• High creep and fatigue strength
• Resistance to grain boundary
• Resistance to grain boundary weakening
5. Iron Base Alloys
• Regular iron and carbon steels have poor tempering and
creep resistance upto 450⁰C
• Plain Carbon steel is alloyed with Mo, W, Va and Cr to
improve creep resistance.
• Iron base Carbon steels:
1. Low alloy steel
2. Medium alloy steel
3. High alloy steel
6. Iron base casting alloys:
1)Iron Chromium alloy
2)Iron Chromium Nickel Alloy
Wrought Iron base alloys: Varying alloy elements
composition
7. Nickel base alloys
• Nickel has very low coefficient of thermal expansion.
• Nickel is alloyed with Cr, Mo, and Co to improve specific
properties.
Different Nickel base alloys are:
1)Ni-Cr
• High resistance to corrosion
• High thermal shock resistance
8. Refractory metals and alloys
• They can withstand very high temperatures.
• High wear and corrosion resistance
• Very low coefficient of thermal expansion
• Due to cost and availability reasons, alloying elements are
used selectively and in smaller proportions
• Refractory ceramics are used in furnaces, crucibles,
molten metal carrying vessels.
9. • They have high abrasion resistance, heat
resistance and can withstand high compressive
stresses.
• Ceramics are mostly crystalline in structure but
due to different chemical compositions their
structure becomes more complex.
• Non metal ceramics have poor thermal and
mechanical shock absorbing resistance.
10. Ceramics and metal ceramics
• Ceramic is a compound formed by combination of
inorganic and non metallic materials.
• It is derived from Greek word Keramos meaning
burnt potter’s clay or earth.
• Ceramics are hard and brittle materials.
