Engineering Materials; Types, Properties.pptx

Engineering Materials; Types, Properties

1. Engineering Materials; Types, Properties Presented By: Md. Tarek Ur Rahman Erin Assistant Professor (Mechanical) Textile Engineering College, Zorargonj , Chattogram .

2. Contents 01 Engineering Materials, Basic Classification of Engineering Materials, Selection of Materials for Engineering Purpose, Properties of Materials, General Properties of the Metals, Properties of Ceramics , Properties of Polymers . Stress-Strain Diagrams and Material Behavior, Mathematical Problem Analysis.

3. Engineering Materials Engineering materials refers to the group of materials that are used in the construction of man made structures and components. The primary function of an engineering material is to withstand applied loading without breaking and without exhibiting excessive deflection.

4. Basic Classification of Engineering Materials Basically Engineering Materials Can be classified into two categories- 1. Metals 2 . Non-Metals Engineering materials can also be classified as below- 1. Alloys 2. Ceramic Materials 3. Organic Materials

5. ??? What’s the difference: 10k Gold, 14k Gold, 18k Gold, 21k Gold, 22k Gold and 24k Gold?

6. Alloys and Composites (and Compounds )

7. Selection of Materials for Engineering Purpose The best material is one which serve the desired objective at the minimum cost. Availability of the materials Suitability of the materials for the working conditions in service The cost of the materials

8. Properties of Materials Mechanical properties Thermal properties Electrical properties Magnetic properties Chemical properties Physical properties

9. Mechanical Properties Strength Elasticity Ductility Malleability Plasticity Toughness Brittleness Corrosive Resistance Abrasion Resistance Fatigue Machinability Hardness

10. Properties of Metal General Physical Properties of the Metals: Shiny appearance; they show a metallic luster. Harder to cut. On being hammered can be beaten into thinner sheets. This property is called Malleability. Most metals are malleable. Gold and Silver metals are the most malleable metals. Most metals are ductile. Good conductors of electricity & heat.

11. Properties of Metal General Physical Properties of the Metals: Metals are generally sonorous. That is, they make a ringing sound when struck. Metals such as iron are very strong. Therefore, it is therefore, widely used in the construction of buildings, bridges, railway lines, carriages, vehicles and machinery. All metals except Mercury, exist in the solid form at room temperature. Therefore, they retain their shapes under normal conditions. High melting points. High tensile strength.

12. Properties of Metal General Chemical Properties of the Metals: Metals when burned in the presence of oxygen, they combine with oxygen to form metallic oxides which are basic in nature. Metal hydroxide changes red litmus blue which shows its basic characteristics. Most metals corrode when they are exposed to atmosphere. Metals differ in their reactivity with acids. Most metals react with acids to produce salts and hydrogen.

13. Properties of Ceramics The Physical and Chemical Properties of Ceramics: High melting points (so they're heat resistant). Great hardness and strength. Considerable durability (they're long-lasting and hard-wearing). Low electrical and thermal conductivity (they're good insulators). Chemical inertness (they're unreactive with other chemicals). High dimensional stability. Good wear resistance.

14. Properties of Polymers A polymer is any of a class of natural or synthetic substances composed of very large molecules, called macromolecules, which are multiples of simpler chemical units called monomers. Polymers make up many of the materials in living organisms and are the basis of many minerals and man-made materials. Some of the useful properties of various engineering polymers are high strength or modulus to weight ratios (light weight but comparatively stiff and strong), toughness, resilience, resistance to corrosion, lack of conductivity (heat and electrical), color, transparency, processing, and low cost.

15. Stress-Strain Diagrams and Material Behavior

16. Mathematical Problem

17. Mathematical Problem Q.1. A hollow cylinder 2 m long has an outside diameter of 50 mm and inside diameter of 30 mm. If the cylinder is carrying a load of 25 kN. Find the stress in the cylinder. Also find the deformation of the cylinder, if modulus of elasticity is 200 GPa . Solution:

18. Mathematical Problem Q.2 . A hollow steel tube with an inside diameter of 100 mm must carry a tensile load of 400 kN. Determine the outside diameter of the tube if the stress is limited to 120 MN/m 2 . Solution :

19. Mathematical Problem Q.3. What force is required to punch a 20 mm diameter hole in a plate that is 25 mm thick? The shear strength is 350 MN/m2 . Solution :

20. Thank You