Mechanical tests are conducted to determine mechanical properties by deforming or destroying materials. Key tests include tensile tests to determine strength, compression tests for ductile and brittle materials which must avoid buckling, hardness tests to measure resistance to indentation and abrasion, fatigue tests to analyze failure from repeated stress cycles, and creep tests to examine gradual deformation under long-term loading, especially at high temperatures. The results of these tests inform the design and use of materials for structures and other applications.

1. Mechanical Testing of Materials
Mechanical tests are done to determine mechanical properties by deformation or by destruction.
i. Tensile Test:
The results obtained by tensile test are widely used in the design of materials for structures and other
purposes.
ii. Compression Test:
It is opposite of the tensile test and performed for ductile and brittle materials. Difficulties in performing the
test are:
- Non-parallel top and bottom faces of specimen leads to difficult axial loading.
- Specimen Length is short (about twice of its diameter) to avoid buckling.
- Friction Between ends of specimen and machine affects test results.
iii. Hardness Test:
Hardness test is done to know metal resistance against indentation, penetration and abrasion.
iv. Fatigue Test:
Fatigue failure is caused by repeated stress cycles (reversal of direction of bending or torsion or
alternating compressive and tensile stresses application and removal of stresses). A fatigue crack starts
at some point of stress concentration. The Stress that produces fatigue failure is smaller than the ultimate
tensile stress.
v. Creep Test:
Materials loaded for long periods may gradually deform, and fracture at a stress that is well below the
ultimate tensile stress. This continuous gradual extension under a steady load or steady stress is known
as Creep. Creep is critical at high temperatures and for low-melting-point metals at room temperature.
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