Hooke’s Law and Mechanical Properties

Hooke’s Law ;

Sir Robert Hooke’s (1635 – 1703 ) Law states that the stress is directly proportional to strain upto elastic limit.

Heat Treatment – A combination of operation involving heating and cooling under controlled conditions for obtaining desired properties in a material.

Those properties of a material that define its behavior under applied force are called mechanical properties.

Mechanical Properties ;

These mechanical properties are :
1. Stress – Internal resistance set up in a material on application of load
2. Strain
3. Elasticity – Ability of a material to resume original form/structure after removal of load
4. Plasticity – Ability of a material to retain the form given by load after its removal.
5. Strength
6. Ductility – Ability of a material of being drawn from longer to smaller sections without fracture.
7. Brittleness – Ability of material of fracturing without appreciable deformation under load.
8. Malleability – Ability of a material of getting beaten into thin sections without fracture.
9. Hardness – Ability of a material to resist indentation abrasion of scratching.
10. Toughness – Shock absorbing capacity of material
11. Stiffness – The rate of stress with respect to strain
12. Resilience – Capacity of a material to sore strain energy
13. Creep – Continuous deformation of material under steady load.
14. Fatigue – Failure of a material under load.
15. Limit of Proportionality
16. Elastic Limit
17. Yield Point
18. Ultimate Strength

19. Proof Stress – Stress required to produce permanent strain in a material equal to a specified percentage of its gauge length.
20. Impact Strength
21. Fracture – Fragmentation of a solid body under load.
22. Ductile Fracture
23. Brittle Fracture
24. Machinability –  The ease with which a given material can be removed or cut.
25. Weldability – The ease with which a metal forms a sound joint with its pieces.
26. Formability – Ease with which a material can be deformed into deaired shape whie in solid state wth or without heating.
27 Castability – The ease with which the metal can be cast into sound casting by melting and pouring into moulds.