MAT602 (January 2020 Semester A Exams)
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MAT602 (January 2020 Semester A Exams)
1. Which of the following class of materials typically has the highest specific modulus?
a. Metals
b. Plastics
c. Ceramics
d. Foams
2. Which of the following materials groups contains materials with the highest ability to retain useful properties at high temperatures?
a. Metals
b. Plastics
c. Ceramics
d. Polymer Composites
3. Which of the following does a designer seek to maximise when they design an efficient spring?
a. The density of the spring
b. Energy stored per unit mass
c. The specific strength
d. The modulus
3. Which of the following materials has the highest modulus?
a. Diamond
b. Lead alloys
c. Steel alloys
d. Silicon Carbides
5. The most significant design objective for a competition rowing blade (also known as an oar) is?
a. Minimum mass
b. Maximum modulus
c. Maximum strength
d. Maximum toughness
6. Which of the following materials as a result of its physical properties makes the most suitable electrical insulator in a spark plug?
a. Aluminium Nitride
b. Alumina
c. Silica
d. Silicon Nitride
7. Taking into consideration the issue of ease of recycling, which of the following joining techniques is the least appropriate for use when joining together two injection moulded polymer components, made from the same grade of polymer?
a. Snap closure fasteners
b. Thermal bonding
c. Ultrasonic welding
d. Adhesive bonding
8. Which of the following classes of materials can be blow moulded most easily?
a. A borosilicate glass
b. A crystalline ceramic
c. A glass filled polymer composite
d. A thermosetting rubber
9. Which of the following is conventionally considered to be the most suitable processing route for manufacturing a plastic tooth brush?
a. Injection moulding
b. Blow moulding
c. Extrusion
d. Rotational moulding
10. Which of the following metals has the highest melting temperature?
a. Tungsten
b. Iron
c. Gold
d. Aluminium
11. Which of the following statements about casting metals is most true?
a. Heat has to be added to the casting to allow it solidify.
b. The last part of the casting to solidify has the purest composition of the entire
casting.
c. Shrinkage of the casting away from the tooling wall accelerates the cooling rate.
d. Castings always include chemical inclusions.
12. Fracture toughness KC is typically expressed using which of the following SI units?
a. MPa m1/2
b. MPa m-1/2
c. kJ m-1
d. kJ m
13. One metal casting process, involves making a mould by encapsulating a low melting point materials inside a hard shell. The low melting point material is then melted out to leave the mould cavity. This is then used to cast the part, which is removed from the mould by smashing off the hard shell. What is this process known as?
a. Sand casting
b. Investment casting
c. Die casting
d. Continuous casting
14. Which of the following is present in a solid solution strengthened interstitial metal alloy?
a. The solute atoms precipitate out into the crystalline lattice on cooling.
b. The solute atoms replace atoms in the solvent crystal lattice.
c. The atoms have to be almost identical in size between the solvent and the
solute in the alloy.
d. The solute atoms fit into spaces between the solvent atoms, which distorts the lattice.
15. Which of the following statements is true about hot working of metals when compared to cold working?
a. Hot working increases the amount of further plastic deformation that is possible.
b. The recrystallisation process in hot working fixes the previous distribution of dislocations in place.
c. Hot working produces a material with a higher hardness than cold working.
d. The recrystallisation process is slower at a higher temperature.
16. Which of the following primary forming processes is most likely to be used to manufacture an engine block for a petrol engine?
a. Investment casting
b. Die casting
c. Sand casting
d. Extrusion
17. The hardenability of a metal can be determined using which of the following tests?
a. Lorimer test
b. Jominy test
c. Clark test
d. Bremner test
18. Which of the following processing facilities are most suitable for the recycling of scrap steel into new steel products?
a. Blast furnace
b. Continuous casting furnace
c. Electric arc furnace
d. Vacuum degassing furnace
19. Which of the following is the term used to describe an extruded or injection moulded part that is then blow moulded to a larger dimension?
a. Athenson
b. Berlinson
c. Parison
d. Londonson
20. Which of the following statements is the most correct when considering fibre reinforced polymer composites?
a. To ensure the fibres are effectively wet out by the resin it is important that the resin has a low viscosity.
b. To ensure the fibres are effectively wet out by the resin it is important that the resin has a low thermal conductivity.
c. To ensure the fibres are effectively wet out by the resin it is important that the resin has a low specific heat capacity.
d. To ensure the fibres are effectively wet out by the resin it is important that the resin has a low thermal expansion coefficient.
21. Which of the following statements is generally true about thermosetting polymers?
a. They polymerise to form a three-dimensional network.
b. They can be readily recycled using a simple melting process.
c. They are commonly solid before processing and are easily melted by the
action of heat.
d. The chemical reaction transforming the initial liquid into the final 3-D macromolecule, takes place in the mixer prior to moulding.
22. Which of the following statements is the most appropriate way of describing the material polyethylene?
a. At room temperature it is a glassy polymer below its glass transition temperature.
b. It is a thermosetting polymer.
c. It is an amorphous polymer exhibiting rubber like behaviour.
d. It is a semi-crystalline thermoplastic polymer.
23. What is the name of the materials property often known as GC that represents the value of the energy required to create a new unit area of crack?
a. fracture toughness
b. strength
c. modulus
d. toughness
24. Frequently polypropylene is used as a mechanical hinge for applications such as a DVD box cover. How is this possible?
a. The polymer chains in polypropylene are rubber like in behaviour.
b. During moulding the polymer chains in the hinge region do not flow well through the restricted cross section of the hinge region and this creates a flexible hinge as a result.
c. During moulding the polymer flows through the hinge at much higher shear stresses which significantly orientates the polymer chains
d. Polypropylene has a very high fatigue strength compared to all other materials.
25. Which of the following statements most reasonably explains how kettles can be made from plastic that would normally soften significantly if heated to the boiling point of water?
a) The kettle is made from a poor thermally conductive material and therefore only a thin inner section of the kettle wall reaches the softening temperature.
b) The kettle uses a high temperature resistant internal coating such as a metal.
c) The kettle has a switch to prevent the water from boiling.
d) The polymer is highly orientated during moulding and this raises the softening
temperature
26. Which of the following statements is the most accurate description of why some polymeric materials exhibit rubber-like behaviour?
a. The polymer must be above the glass transition temperature.
b. The forces between neighbouring molecules are ionic.
c. The polymer must be semi-crystalline.
d. The polymer should be hydrophobic.
27. The largest volume usage for polymer materials in a 2012 EU study was in which of the following industries?
a. Packaging
b. Automotive
c. Electrical goods
d. Agriculture
28. Which of the following ceramics is the most suitable for use as a cutting tool?
a. Tungsten carbide - WC
b. Barium titanate - BaTiO3
c. Molybdenum disulfide - MoS2
d. Aluminium oxide (Alumina) - Al2O3
29. Optimum packing for rigid spheres of identical size results in how large a void volume fraction?
a. 52%
b. 30%
c. 12%
d. 6%
30. Which of the following four processes typically creates the largest ceramic powder for subsequent processing?
a. Sol-gel processes
b. Freeze drying processes
c. Combustion synthesis
d. Ball milling
31. What provides the driving energy for solid state sintering?
a. Differences in vapour pressure
b. The net movement of material from a positive radius of curvature to a negative
one.
c. Capillary pressure
d. A net increase in the free energy of the system
32. Which of the following ceramic materials is the most suitable for use as a heat sink for a transistor device where high thermal conductivity and low electrical conductivity are important?
a. Aluminium oxide, Al2O3
b. Barium titanate, BaTiO3
c. Molybdenum disilicide, MoSi2
d. Aluminium nitride, AlN
33. One additive manufacturing process uses a laser beam guided by a mirror to trace a single layer onto the surface of a vat of liquid polymer to cure the polymer. The cured material is then lowered a small distance below the remaining liquid, re- coating it with more resin and the process is repeated. This process is known as?
a. Selective laser sintering
b. Stereolithography
c. Laminated object manufacturing
d. Fused deposition modelling
34. Given that the linear thermal-expansion coefficient of a thermally isotropic material is α /K-1 then which of the following values gives an approximate value for the volumetric thermal expansion coefficient?
a. α-1
b. 2α
c. 3α
d. α2
35. In design which of the following equations always applies for a design to be a commercial success?
a. Cost < Value < Price
b. Price < Cost < Value
c. Value < Price < Cost
d. Cost < Price < Value
36. When multiple requirements specify two conflicting goals for a material’s selection process then it is necessary to devise a way of determining the best solution. One approach is to derive a metric that can describe each goal. You can then draw a graph of one metric against the other and evaluate the performance of different materials against each other. A trade off surface appears whereby the best performing materials can be identified. This surface is known as the:
a. Giles front
b. Pareto front
c. Sprake front
d. Charles front
37. Which of the following effective material for use as an O-Ring in a domestic water system?
a. Butyl rubber
b. Cork
c. Natural rubber
d. Polytetrafluoroethylene
38. What is the typical modulus of an engineering elastomer?
a. 10 kPa
b. 1 MPa
c. 100 MPa
d. 1 GPa
39. What is the typical toughness of a steel alloy?
a. 1 kJm-2
b. 100 kJm-2
c. 1 MJm-2
d. 100 MJm-2
40 Which of these materials is the most suitable for use as a competition rowing blade?
a. Balsa wood
b. Polyvinylchloride
c. Carbon fibre reinforced composite
d. Aluminium alloy
41. Which of the following materials indices determines the wave speed in a solid, where E is the modulus of elasticity, is the density and y is the yield strength of the material?
a. ⁄
b.
c.
d.
42. The thermal shock resistance for a material can be calculated from a combination of other properties including the thermal expansion coefficient, the strength of the material and the modulus all measured over the appropriate temperature ranges. In practice the thermal shock can be defined as:
a. The maximum temperature gradient allowable in a structure before it fractures
b. The maximum operating temperature of a structure
c. The maximum rate of heat transfer possible in the structure
d. The maximum number of cycles a structure can experience whilst it is being
fatigued at elevated temperature
43. How much of its weight does a domestic car tyre loses throughout its normal life?
a. 5%
b. 10%
c. 20%
d. 30%
44. Shielded metal arc welding involves which of the following processes?
a. A laser beam is focused on the joint, creating a plasma, and local melting.
b. An electric arc is formed between an electrode and the metals to be joined, which all melt. The flux coating of the electrode forms a shielding gas and provides a layer of slag to protect the weld.
c. The weld is produced by heating using a focused beam high velocity electrons.
d. An arc between a non-consumable tungsten electrode and the torch is used to transform inert gas into plasma. This plasma is then used to melt the workpiece and filler metal.
45. Which of the following relations between the elastic constants: the tensile modulus, E; the shear modulus, G; the bulk modulus, K and Poisson’s ratio is correct?
a. = − 1
b. = 2
c. =
d. All of the above
46. The most commonly applied interleavant materials currently used throughout the glass industry is:
a. Polymethymethacrylate
b. Polyvinylchloride
c. Polypropylene
d. Polyisoprene
47. Which of the following statements is the most correct description of the glass transition temperature, Tg of a polymer?
a. Tg is the temperature above which a polymer exhibits glassy like behaviour.
b. Tg is the temperature above which an amorphous polymer exhibits rubber like
behaviour.
c. Tg is the temperature at which the polymer crystals in a semi-crystalline polymer melt.
d. Tg is the boiling temperature for the polymer.
48. The Wiedemann-Franz law is best summarised by which of the following statements?
a. The elastic modulus of different materials is linearly related to its yield strength.
b. The strength of different materials is linearly related to its density.
c. The electrical and thermal conductivities of materials are broadly linearly
related.
d. The toughness of different materials is linearly related to its thermal conductivity.
49. Which of the following materials formed into a solid cube would have the highest strength in compression?
a. Ultra high density polyethylene
b. Glass fibre composites
c. Silicon carbide
d. Natural rubber
50. Which of the following materials indices values should be maximised to identify the best materials for a lightweight but stiff beam?
a. E1/3/
b. E1/2/
c. E/
d. E2/
2021-12-20