Classification of Materials

• Metals & Alloys:
  • Iron & Steels: The modulus of elasticity for this group ranges from 180-217 GPa. The yield strength has a wider variation range; from 250-2250 MPa. The fracture toughness ranges from 12-210 Mpa-m^1/2 and the service temperature from -70 to 600⁰C. Starting from the reinforcement of concrete to bridges, cables, shafts, gears, springs, bearings, car-bodies and food-processing equipments, the iron and its alloys have found every conceivable applications in our life-style.
    
    
  • Aluminium & alloys: The modulus of elasticity is lower than Iron & Steel; from 65-90 GPa. The yield strength is relatively high; from 30 to 510 MPa. The fracture toughness is quite low in comparison to steel; from 18-40 MPa-m^1/2. Range of service temperature is moderate from -270 to 200⁰C. The relatively inferior mechanical properties of Aluminum are shielded often by its' light weight and excellent thermal and electrical properties. Major usage of Aluminium is in the Aerospace industry. New applications are in the field of car-body construction and electronics packaging.
    
    
  • Copper & alloys:
    
    
• Nickel & Alloys: Nickel has excellent mechanical properties at high temperature – particularly in the form of alloys. The elastic modulus varies from 125-245 GPa; comparable to steel. The yield strength from 20-2100 MPa, again comparable to steel. The service temperature could be as high as 1200⁰C. This is one of the reasons why Nickel & its alloys are used to form super alloys. Such materials are widely used in Turbine blades.
  
• Titanium & Alloys: The elastic modulus and yield strength of titanium alloy are slightly lower than steel (modulus 90-140 GPa, strength 170-1250 MPa). However, it is lighter than steel and it has a good service temperature (-40 to 500^oC). The materials are mostly used in the aerospace industry.