Short Question – Materials Engineering | AKTU Important Short Questions.

In this article, we are discussing for Short Question in Materials Engineering, Here we cover all unit’s Short Question with solutions. Hope this Short Questions will help you in your upcoming Exams.

Unit – 1 (Crystal Structure and Mechanical Property Measurement)

Q1.  Define crystal structure.

Ans. In a solid, the arrangement of the unit cell, a small representative group of atoms or molecules, is referred to as the crystal structure.

Q2. What do you mean by amorphous materials ? 

Ans. Amorphous materials are those in which the arrangement of atoms over a significant amount of atomic distance is random and uneven.

Q3. What is a unit cell ?

Ans.  A unit cell is a small group of atoms arranged in three dimensions.

Q4. What is coordination number ?

Ans. The coordination number is the sum of the distances between each atom in a unit cell and its nearest and equally distant neighbours.

Q5. What is a ceramic material ? Give any two examples. 

Ans. Ceramic Material: The mixture of metallic and non-metallic elements known as ceramics has a predominately ionic interatomic bonding. These materials are typically heat treated at high temperatures to give them the desired characteristics.

 Examples: Clay products, abrasives. 

Q6. Write down any four properties of ceramic materials.

Ans. Properties of ceramic materials are as follows 

• i. They have a very fragile character and are very hard.
• ii. They carry heat and electricity poorly. 
• iii. Compared to metals, they are relatively stiff and robust. 
• iv. They are more resistant to high temperatures. 

Q7. What are refractory materials ? Give some examples. 

Ans. Refractory Material: These are the heat-resistant materials that can tolerate high temperatures, have a strong enough mechanical structure, resist heat, and keep their volume constant. 

Examples: Graphite, thoria, zirconia, fireclay bricks. ]

Q8. What do you mean by imperfect crystal? 

Ans. A perfectly ordered arrangement of atoms is said to be imperfect if there is some deviation or unpredictability.

Q9. Write down the different types of crystal imperfection. 

Ans. The crystal imperfection are as follows: 

• i. Point imperfection, 
• ii. Line imperfection, 
• iii. Surface imperfection, and 
• iv. Volume imperfection. 

Q10. What are the different types of point imperfections?

Ans. The point imperfection are as follows: 

• i. Vacancy, 
• ii. Substitutional impurity, 
• iii. Interstitial impurity, 
• iv. Frenkel’s defect, and 
• v. Schottky’s defect.

Q11. Explain the edge dislocation in short.  

Ans. Edge dislocations are a defect that develops when the crystal acquires an additional partial plane of atoms.

Q12. Differentiate between edge dislocation and screw dislocation. 

Ans. 

Q13. What are the different ways of dislocation strengthening? 

Ans. Following are the three ways of dislocation strengthening: 

• i. Strengthening by grain size reduction, 
• ii. Solid solution strengthening, and 
• iii. Strain hardening. 

Q14. What is Frenkel’s defect ?

Ans. Frenkel’s defect is created when a cation shifts from its normal site to an interstitial location. The crystal’s electrical neutrality is unaffected by this flaw.  

Q15. What is Sehottky’s defect? 

Ans. Schottky’s defect is created when a pair of cations and anion are taken out of an ionic crystal unit cell.

Q16. Define the term Young’s modulus. 

Ans. The ratio of compressive stress to compressive strain, or vice versa, is known as the Young’s modulus.

Q17. What is Hooke’s law ?  

Ans. According to Hooke’s law, when a material is loaded up to its elastic limit, the stress and strain are directly proportional.

Q18. Define the term ductility. 

Ans. Under the influence of a tensile force, a material can be stretched out lengthwise to a smaller portion thanks to a property called ductility.  

Q19. Differentiate between toughness and resilience. Also define the endurance limit. 

Ans. Difference between Toughness and Resilience: 

Endurance Limit: The level of limiting stress below which a load may be repeatedly applied a very large number of times endlessly.

Q20. Why yield points occurs in low carbon steel ?

Ans. Because of the interstitial carbon and nitrogen atoms in low carbon steel, the yield point phenomenon arises.

Q21. What are the drawbacks of Brinell hardness test ? 

Ans. Drawbacks of Brinell hardness test are as follows 

i. Sinking effect, and 

ii. Piling-up effect.

Q22. What do you mean by shore hardness test ?

Ans.  The shore hardness test is appropriate for figuring out how hard very soft and thin metals and non-metals are. Durometer is the name of the shore testing instrument.

Q23. A hardened steel ball of 0.50 cm diameter is used to indent a steel specimen in Brinell hardness test. Diameter of indentation measured by an optical microscope of magnification 10 X is observed to be 32.5 mm. Calculate Brinell hardness number of the steel specimen. 

Ans. Given: D= 0.50 cm 5 mm, d= 32.5 mm 

To Find : Brinell hardness number of the steel specimen. 

1. Load stage for steel specimen = 30 D²

          P = 30 D² = 30 x (5)² = 750 kgf 

2. The hardness is obtained as, 

Unit – 2 (Static Failure Theories and Fracture Mechanics)

Q1. Why brittle fracture is more dangerous than ductile fracture?

Ans. Brittle fracture is more dangerous than ductile fracture because : 

i. Due to the quick crack propagation, brittle fracture happens abruptly and without any prior notice. 

ii. Less strain energy is needed for fracture in brittle fracture.

Q2. Draw the stress strain diagram for brittle materials and explain. 

Ans. Fig.  shows the stress-strain diagram for brittle materials, in which the axial strain are plotted along x-axis and corresponding stresses are plotted along y-axis.

Q3. Write important criteria of yielding. 

Ans. Most Important criteria of yielding are: 

i. Tresca’s yield criteria, and 

ii. Von mises yield criterïa.

Q4. Describe maximum normal stress theory. 

Ans. According to this hypothesis, when the maximal normal stress reaches the yield or ultimate strength of the material, the mechanical component subjected to biaxial or triaxial forces fails. 

Q5. Define Mohr-Coulomb failure theory. 

Ans. A mathematical model called the Mohr-Coulomb theory describes how brittle materials, such concrete or rubber piles, react to both normal and shear stress.

Q6. Define fatigue life. 

Ans. The number of stress cycles that the standard specimen may complete during the test before the first fatigue crack appears is known as the fatigue life.

Q7. What is S-N curve ? 

Ans. On a piece of log-log graph paper, the stress amplitude (S) vs the number of stress cycles (N) until the fatigue failure are represented graphically as the S-N curve.

Q8. What is the difference between low cycle fatigue and high cycle fatigue ?  

Ans. 

Q9.  What is fatigue phenomenon ? 

Ans. A structure (such as a bridge, an aircraft, or a machine component, etc.) can fail through fatigue when it is subjected to dynamic and fluctuating loads.

 Q10. Write down the types of fatigue loading.

Ans. Types of fatigue loading are as follows Zero-to-max-to-zero. 

i. Variable load on top of a steady load. 

ii. Fully-reversing load.  

Q11. Write down some fatigue properties. 

Ans.  Some fatigue properties are as follows: 

i. The longer fatigue lives, the more frequently fatigue lives dispersed. 

ii. Damage is cumulative. 

Q12. What is the need of fatigue testing? 

Ans. To ascertain a material’s ability to tolerate repeatedly applied stress, fatigue tests are carried out in the lab.

Q13. Define the term strain hardening. 

Ans. The process of reinforcing a metal or polymer through plastic deformation is known as strain hardening.

Q14. Define non-destructive testing.  

Ans.  Non-destructive testing is a technique for examining engineering materials without damaging them to find internal faults.

Q15. Differentiate between destructive and nondestructive testing. 

Ans. 

Q16. Write down the advantages of non-destructive testing. 

Ans. Advantages of non-destructing testing are as follows:

• i. Analysis of parts can be done without breaking it.
• ii. Cost saving procedure. 
• iii Improves the quality of production. 
• iv. Saves time in product evaluation. 

Q17.  Name some of the methods used for non-destructive testing.  

Ans. Some methods used for non-destructive testing are as follows: 

• i. Visual inspection, 
• ii. Eddy current testing, 
• iii. Magnetic particle inspection, and 
• iv. Penetrant testing 

Q18. Write down the factors on which stress intensity factor depends. 

Ans. Following are the factors on which stress intensity factor depends: 

• i. Sample geometry, 
• ii. Size and location of the crack, 
• iii. Magnitude of load, and 
• iv. Distribution of load.

Unit – 3 (Phase Diagram)

Q1. What do you mean by solid solution ?

Ans. A solid solution is a mixture of one or more solutes in a solvent that has solidified.

Q2. What is substitutional solid solution ? 

Ans. The solute will randomly replace one of the matrix atoms in the f crystal lattice if the two atoms are similar in size. A substitutional solid solution is the name given to this form of structure. 

Q3. What are the types of Ans substitutional solid solution ?

Ans. Types of substitutional solid solution are as follows: 

• i. Random substitutional solid solution, and 
• ii. Ordered substitutional solid solution.  

Q4. What is interstitial solid solution ? 

Ans.  When there are spaces between the atoms of the solvent that can accommodate a few relatively tiny atoms, an interstitial solid solution is created.

Q5. What is phase diagram ? 

Ans. Phase diagrams are graphical depictions of the phases that are present in a system of materials at different temperatures, pressures, and compositions. 

Q6. Write down the types of phase diagram. 

Ans. Types of phase diagram are as follows: 

• i.Unary phase diagram, 
• ii. Binary phase diagram, and 
• iii. Ternary phase diagram. 

Q7. What are the informations required for interpretation of phase diagrams ? 

Ans. Information required for interpretation of phase diagrams are:

• i. Phases present. 
• ii. Composition of phases. 
• iii. Fraction of phases.

Q8. What is eutectic phase diagram ?

Ans. The phase diagram is known as a eutectic phase diagram when there is only a little difference between the melting points of the two components and there is little to no solid solubility between them.

Q9. What do you understand by eutectoid reaction ?

Ans. A solid phase can change into two other solid phases upon cooling in the eutectoid process, and vice versa. 

Q10. What is peritectic phase diagram ? 

Ans.  When the melting points of two components diverge too much from one another, a peritectic phase diagram is produced. An illustration of a peritectic phase diagram is the gold-lead system. 

Q11. What do you understand by monotectic reaction ? 

Ans. A liquid can become a solid or another liquid through a monotectic reaction.

Q12. What is the use of lever rule ?

Ans. It is used for the estimation of: 

• i The fraction of a proeutectic phase. 
• ii. The fraction of the eutectic mixture. 
• iii. The fraction of phase that form eutectic mixture.

Q13. Give the limitation of lever rule.  

Ans. Eutectic or peritectic temperatures preclude the application of the lever rule. 

Q14. Define the term ledubrite.  

Ans. Ledeburite is an iron combination containing 4.3% carbon. Austenite and cementite are mixed in a eutectic manner.

Q15. Define the term cementite. 

Ans. Cementite is an intermittent compound made up of a certain lattice arrangement of iron and carbon atoms. Pearlite is a laminated structure that is formed when ferrite and cementite are combined in the right proportions.

Q16. Write down the significance of iron-carbon equilibrium diagram. 

Ans. The iron-carbon diagram is crucial for understanding iron and the behaviour of iron alloys. It serves as the foundation for cast irons and commercial steels, and it has the power to change how most complicated alloy steels behave. 

Unit – 4 (Heat Treatment of Steel)

Q1. What is heat treatment? 

Ans.  Heat treatment is the process of heating metal and then cooling it under different environmental circumstances in order to control or enhance the metal.

Q2. What are the purposes of heat treatment ?

Ans. Purposes of heat treatment are as follows:

• i.  Create the interior rough areas and the surfaces. 
• ii. Modify magnetic and electrical properties. 
• iii. Improve machinability. 
• iv. Refine the grains. 

Q3. What are the types of annealing ? 

Ans. Types of annealing are as follows: 

• i Process annealing, 
• ii. Full annealing, 
• iii. Spheroidal annealing, 
• iv. Diffusion annealing, 
• v. Recrystallization annealing, and 
• vi. Stress relief annealing.  

Q4. What is stress relief annealing?

Ans. In the process of stress alleviation critical annealing, steel is heated to a lower temperature than necessary and maintained there for a period of time before being progressively cooled. 

Q5. Write down the objective of annealing. 

Ans. Objective of annealing are as follows : 

• i It softens the steel. 
• ii. It Improves ductility of steel. 
• iii. It enhances machinability. 
• iv. It refines the grain structure 

Q6. Define tempering.

Ans. Hardened steel is warmed below its lower critical temperature (723 °C) and then slowly cooled during the tempering process. 

Q7. What are the purposes of tempering?

Ans. Purposes of tempering are as follows: 

• i. It reduces brittleness of hardened steel. 
• ii. It increases ductility. 
• iii. It relieves internal stresses. 
• iv. It improves toughness of steel. 

Q8. Define normalizing process.  

Ans. Steel is heated up to 40–53 °C over the upper critical temperature during the normalizing process, kept there for a predetermined amount of time, and then allowed to cool in the air. The cooling rate is higher than annealing at about 25 to 30 °C/hour.

Q9. Why hardening is followed by tempering? 

Ans. Tempering is performed after hardening since the parts produced cannot be utilized directly because to their high stress state, which may result in deformation and cracking when put or used at room temperature.  

Q10. What is recrystallization temperature ?

Ans. Recrystallization temperature is the lowest temperature for a given alloy at which complete recrystallization will take place in about an hour. 

Q11. What is TTT diagram ?  

Ans. The relationship between the beginning and end of the production of various microstructures is represented by the temperature-time-transformation diagram. 

Q12. Define ‘critical cooling rate’ in TTT diagram with neat sketch. 

Ans. The snout of the curve in a TTT diagram represents the transformation that takes the least amount of time. Critical cooling rate is the slope of the line that goes through this nose (C-curve).

Q13. What is austempering process ?

Ans. In the heat-treatment procedure known as austempering, steel is first austenitized before being quenched in a salt bath kept at a constant temperature between 260 and 400 °C.

Q14. What do you mean by carburizing?

Ans.  Steel is subjected to the carburizing process, which results in a hard, wear- and shock-resistant surface with a robust interior core. During this procedure, carbon is pushed into the surface structure of the steel after it has been heated to a red-hot temperature.

Q15. What are the different types of case hardening?

Ans. Different types of case hardening are as follows: 

• i. Pack carburizing. 
• ii. Liquid carburizing, and 
• iii. Gas carburizing. 

Q16. What is pack carburizing? 

Ans.  A steel box containing a rich carbon powder is used to load the carburizing specimen. After that, the box is gradually heated above the lower critical temperature, and soaking is completed. After soaking, the box is progressively cooled.

Q17. What is quenching process ? 

Ans. To get specific material qualities, a workpiece is rapidly cooled in water, oil, or air. The surface of a hot object will cool more quickly than the inside when put into a quenching medium. 

Q18. What is liquid carburizing ?

Ans. In the process of liquid carburizing, a jet of liquid carbon is utilized to impact the heated steel. As a result, carbon accumulates on the steel.

Q19. What do you mean by cyaniding?

Ans.  We cyanided the component by submerging it in a bath of sodium cyanide (NaCN) heated to 400 °C. The sodium cyanide bath is used to finish the soaking procedure. Metal or steel is quenched in oil to harden the surface once it has finished soaking.

Q20. Write down the disadvantages of nitriding. 

Ans. Disadvantages of nitriding are as follows: 

• i. High cost, and 
• ii. More time consumption to complete the process.

Q21. Define age hardening.

Ans. Age hardening is the process of strengthening an alloy by causing the last dispersed phase to precipitate from a supersaturated solid solution.

Q22. What do you understand by flame hardening? 

Ans. Heating and quenching are both done at the same time for flame hardening. Oxy-acetylene flame is used to heat the component over the critical temperature while water is sprayed under pressure onto the metal’s surface.

Q23. What is induction hardening?

Ans. In the process of induction hardening, the specimen is heated by submerging it in a powerful magnetic field. An alternating current induces and generates a heating effect on the specimen’s surface as a result of the magnetic field and flux change. By sprinkling cold water, a simultaneous quenching procedure is carried out. 

Q24. Write down the advantages of induction hardening.  

Ans. Advantages of induction hardening are as follows:

• i. Heating times are extremely short. 
• ii. No surface oxidation. 
• iii. Heat treatment-related deformation is significantly decreased.
• iv. Enables heat treatment processes to be automated.

Unit – 5 (Metals and their Alloys)

Q1. Define an alloy. 

Ans. A metallic material called an alloy is made up of two or more elements.

Q2. Why do we use alloy in steels ?

Ans. Alloy in steels are used: 

• i To form martensite without cracking of steel. 
• ii. To enhance hardenability. 
• iii. To impart toughness. 
• iv. To increase ductility etc.  

Q3. Why chromium is added into the alloys ?

Ans. Chromium is added into the alloys because of following reasons: 

• i. It increases hardenability. 
• ii. It increases high temperature strength.  

Q4. What are the applications of low carbon steel ?

Ans.  Following are the applications of low carbon steel 

• i. Automobile body components, 
• ii. Structural shapes such as I-beam, channels ete., 
• iii. Pipelines, buildings, bridges, and 
• iv. Tin cans.

Q5. Where do we use medium carbon steels ?

Ans. Medium carbon steels are used in: 

• i Railway wheels and tracks, 
• ii. Gears, 
• iii. Crankshafts, 
• iv. Machine parts, and 
• v. High strength structural components. 

Q6. What are the applications of high carbon steels ? 

Ans. Application of high carbon steels are as follows: 

• i Cutting tools and dies for forming and shaping materials, 
• ii Hacksaw blades, and 
• ii. Springs.

Q7. What are basie types of cast iron ? 

Ans. Types of cast iron are as follows: 

• i. Grey cast iron, 
• ii. White cast iron, 
• iii. Ductile cast iron, and 
• iv. Malleable cast iron.  

Q8. Write the properties of cast iron. 

Ans. Properties of cast iron are as follows: 

• i Cast iron is very cheap engineering material. 
• ii. It has good hardness due to presence of carbon percentage. 
• iii. It can be machine easily due to good machinability 
• iv. It has very good rigidity.  

Q9. How is cast iron produced? 

Ans. Pig iron is melted with coke and limestone in a cupola furnace, where coke is used as fuel and limestone as a flux, to create cast iron.

Q10. Write the properties of aluminium.  

Ans. Properties of aluminium are as follows: 

• i. Light weight, 
• ii. Corrosion resistance, 
• iii. Reflectivity, and 
• iv. Ductility. 

Q11. What is duralumin ? Give the composition and their applications. 

Ans. Duralumin: It is sometimes referred to as an aluminium wrought alloy. Its tensile strength can be improved up to 400 MPa with age hardening and heat treatment. 

Composition: 3.5 % Cu, 0.5 % Mn, 0.5 % Mg and 95.5 % Al. 

Uses: It is mostly used for casting but it may also be used in forged components.

Q12. Write the properties of magnesium. 

Ans. Magnesium is a strong, lightweight metal with a gleaming silver or grey hue.

Q13. Write effect of nickel on property of steel.

Ans. Effects of nickel on property of steel are as follows: 

i It increases toughness. 

ii. It improves forming properties of stainless steel. 

Q14.  Write the properties of titanium. 

Ans.  Properties of titanium are as follows: 

• i High strength, 
• ii Stiffness, 
• iii. Toughness, 
• iv. Low density, and 
• v. Good corrosion resistance. 

Q15. What are the different types of stainless steel ?

Ans. Following are the three types of stainless steel: 

• i. Martensitic stainless steel, 
• ii. Ferritic stainless steel, and 
• iii. Austenitic stainless steel. 

Q16. Write down the properties of maraging steel. 

Ans. Properties of maraging steel are as follows: 

• i. Ultra high strength at room temperature. 
• ii. It can be easily fabricated. 
• iii. It has good weldability. 

Q17. Name the difference types of bronze?

Ans. Different types of bronze are as follows:

• i. Phosphor bronze
• ii. Silicon bronze, and
• iii. Aluminium bronze.

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