17 Engineering Material Properties: Mechanical Engineers Must Know

1. 17 Engineering Material Properties: Mechanical Engineers Must Know

2. Whether it is any branch of mechanical engineering like automobile engineering, knowing the properties is a must. If you are pursuing a mechanical engineering career, then you must keep looking into this space. You should be clear with all the basics of mechanical engineering and you must excel with the technical skills of a mechanical engineer.The jobs for mechanical engineers are vast and versatile but you need proper grooming from the start.

3. The Mechanical properties associated with metals are: 1. Strength The capacity of a material to withstand the load without failure is called strength. If a material can bear more loads, it means more strength. Strength depends on the type of loading and distorts before fracture. According to loading types, strength is classified into three types. • Tensile • Compressive • Shear According to the deformation before fracture, strength can be classified into three types. • Elastic • Yield • Ultimate

4. 2. Elasticity The capacity of a material to regain its original dimension after removal of the load. The material is elastic material and the property is elasticity. Every material has some elasticity. It is a measure of the ratio of stress to strain under the elastic limit. 3. Isotropy: A material with elastic properties along its all loading direction is called material.

5. 4. Anisotropy: A material exhibiting various elastic properties in the various direction of loads is called an-isotropic material. 5. Homogeneity A material that retains properties throughout the geometry is called as homogeneous material and the property is called homogeneity. It is an ideal situation but the fact is that no material is homogeneous.

6. 6. Plasticity: The ability of a material to have some degree of permanent deformation without failure after removal of loads. The property is used for shaping material by metal working. It mainly depends on temperature and elastic strength of the material. 7. Ductility The property by virtue of which metal can be made into wires. It is a property which allows permanent deformation before fracture. The amount of permanent deformation determines if the material is ductile or not. Percentage elongation = (Final Gauge Length – Original Gauge Length)*100/ Original Gauge Length If the percentage elongation is more than 5% in a length of 50 mm, the material is ductile and if it lesser than 5% it is not.

7. 8. Brittleness The property with the help of which, a material will fail under loading without significant change in dimension. Glass and cast iron are well known brittle materials. 9. Toughness The ability to withstand plastic or elastic deformation without any fail. It is defined as the amount of energy absorbed before actual fracture.

8. 10. Stiffness The ability of a material to resist elastic deformation while loading. 11. Hardness The property of a material to have a good resistance to penetration is hardness. It is an ability to resist scratch, or cut. It is also defined as an ability to resist fracture under point loading. 12. Machine-ability A property which helps in the easy cutting of a material. 13. Malleability: The property which helps a metal to flatten into thin sheets, called malleability.

9. 14. Damping The capacity to dissipate the energy of vibration or cyclic stress is called damping. Cast iron has a very good damping property; hence most of the machine’s body is made of cast iron. 15. Creep The slow but continuous change in dimension of a material when influenced by its working stress for a long time is called creep. Creep depends on time and temperature. 16. Embrittlement When a metal loses ductility due to physical or chemical changes and becomes brittle, it is called embrittlement.