Term
-Material Properties in Metal Forming-
Desirable material properties |
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Definition
| Low yield strength and high ductility |
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Term
| Advantages of cold forming |
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Definition
1) Better accuracy, closer tolerances
2) Better surface finish
3) Strain hardening increases strength and hardness
4) Grain flow can cause desirable directional properties
5) No heating of work required |
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Term
| Disadvantages of cold forming |
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Definition
1) Higher forces and power required
2) Surfaces of starting workpiece must be free of scale and dirt
3) Ductility and strain hardening limit the amount of forming that can be done |
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Term
| Which of the following are the three basic types of static stresses to which a material can be subjected? (a) compression, (b) hardness, (c) reduction in area (d) shear (e) tensile, (f) true stress and (f) yield |
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Definition
(a) compression
(d) shear
(e) tensile |
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Term
| The following methods will increase metal's fatigue strength (a) induce compression residual stress (b) induce tensile residual stress (c) reduce surface roughness (d) increase surface roughness (e) strengthen the surface layer by work hardening |
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Definition
(a) induce compression residual stress
(c) reduce surface roughness
(e) strengthen the surface layer by work hardening |
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Term
| If stress values were measured during a tensile test, which of the following would have the higher value? (a) engineering stress (b) true stress |
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Definition
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Term
| Which one of the following types of stress strain relationship best describes the behavior of brittle materials such as ceramics and thermosetting plastics? (a) elastic and perfectly plastic, (b) elastic and strain hardening (c) perfectly elastic or (d) none of the above |
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Definition
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Term
| T or F: The plastic region of the stress- strain curve for a metal is characterized by a proportional relationship between stress and strain |
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Definition
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Term
| T or F: Endurance limit is the stress below which the material will not fail regardless of the number of cycles |
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Definition
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Term
| T or F: Fatigue strength is the maximum stress that can be sustained for a number of loading cycles |
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Definition
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Term
| T or F: The density of materials will always increase as the temperature decreases |
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Definition
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Term
| Which of the following processes are going to increase the strength of material? (a) strain hardening (b) precipitation (c) solid solution (d) annealing (e) grain size refinement |
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Definition
(a) strain hardening
(b) precipitation
(c) solid solution
(e) grain size refinement |
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Term
| The purpose of annealing is to: (a) Produce a uniform structure (b) provide a stress relief (c) induce recrystallization (d) increase ductility |
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Definition
(a) Produce a uniform structure
(b) provide a stress relief
(c) induce recrystallization
(d) increase ductility |
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Term
| If you are asked to design an alloy to improve hardenability, please select one from the following: (a) after the alloying design, the CCT curve moves to the right (b) After the alloying design, the CCT curve moves to the left |
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Definition
| (a) after the alloying design, the CCT curve moves to the right |
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Term
| T or F: A phase is any homogeneous mass of material such as a metal in which the grains all have the same crystal lattice structure, chemical composition |
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Definition
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Term
| T of F: A solid solution is a single phase |
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Definition
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Term
| T of F: Six mechanisms for increasing strength are solid-solution strengthening, strain hardening, grain size refinement, precipitation hardening, dispersion hardening, and phase transformation |
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Definition
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Term
| T or F: In overaging, coherency between precipitation and matrix is broken and new structure will be formed |
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Definition
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Term
| T or F: The strength and hardness will increase in overaging |
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Definition
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Term
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Definition
1) porous part
2) thermal shrinkage
3) bad surface |
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Term
| How to reduce casting defects during casting |
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Definition
1) directional solidification
2) proper pouring rate
3) using smooth molding materials |
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Term
| What are the advantages of casting processes? |
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Definition
1) create complex geometry parts
2) create both external and internal shapes
3)suited to mass production |
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Term
| Which if the following materials are usually used for expendable mold: (a) sand (b) plaster (c) ceramic (d) steel (e) concrete |
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Definition
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Term
| Types of reinforced polymers include: |
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Definition
1) particle
2) fiber
3) flake
4) laminate |
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Term
| T or F: Extrusion process is typically used for long plastic products with a uniform cross-section area |
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Definition
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Term
| T or F: Columnar zone has better mechanical property than chill zone |
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Definition
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Term
| T or F: The purpose of directional solidification is to have the region of casting closest to the riser freeze first |
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Definition
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Term
| T or F: Expendable mold could not be reused and permanent mold could be reused |
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Definition
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Term
| T or F: Thermoplastic materials normally have higher melting point than thermosetting materials |
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Definition
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Term
| T or F: Thermoplastic materials normally have higher stiffness than thermosetting materials |
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Definition
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Term
| T or F: Strength of composite will increase with fiber content increasing |
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Definition
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Term
| T or F: Continuous fiber reinforced composite normally have higher strength than discontinuous fiber reinforced composite |
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Definition
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Term
| T or F: In open die forging, friction between work and die surfaces causes inhomogeneous deformation and results in barrel shape |
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Definition
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Term
| T or F: In forging, the work is under tri-axial compression |
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Definition
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Term
| T or F: The stress status of materials during wire and bar drawing process is triaxial compression before it comes to the die |
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Definition
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Term
| T or F: In extrusion, the work is bi-axial compression and tension before it comes to the die |
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Definition
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Term
| T or F: In metal cutting operations, the cutting force is proportional to shearing strength |
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Definition
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Term
| T or F: In metal bending process, the bending force is proportional to shearing strength |
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Definition
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Term
| T or F: In cluster roll configuration of rolling, the cluster roll can reduce the stiffness of the rolling stystem |
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Definition
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Term
| T or F: Impression die forging can be used to generate more complex 3D shaping than that in flashless die forging |
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Definition
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Term
| T or F: The ram force during indirect extrusion is higher than that in direct extrusion |
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Definition
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Term
| Which of the following are advantages and characteristics of hot working relative to cold working? (a) Fracture of work-part less likely (b) increased strength properties (c) isotropic mechanical properties (d) less overall energy required (e) lower deformation forces required (f) more significant shape changes are possible |
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Definition
(a) Fracture of work-part less likely
(c) isotropic mechanical properties
(e) lower deformation forces required
(f) more significant shape changes are possible |
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Term
| What are the three deformation processes involved in deep drawing? |
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Definition
1) stretching
2) compression
3) bending |
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Term
| What are the advantages of using thread rolling vs. machining for making threads? (a) Higher production rates (b) better accuracy (c) better material utilization (d) stronger threads due to work hardening (e) better fatigue resistance due to compression stresses introduced by rolling |
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Definition
(a) Higher production rates
(c) better material utilization
(d) stronger threads due to work hardening
(e) better fatigue resistance due to compression stresses introduced by rolling |
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Term
| T or F: Traditional metal machining processes remove materials by a sharp cutting tool, while nontraditional machining processes use various energy forms other than sharp cutting tools to remove materials |
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Definition
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Term
| T or F: Roughing process uses high feed rates and high depths of cut and low cutting speeds |
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Definition
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Term
| T or F: Finishing process uses low feed rate and low depths and high cutting speeds |
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Definition
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Term
| The advantages of metal machining processes are (a) waste of material (b) time consuming compared to alternative shaping processes, such as casting, powder metallurgy, or forming (c) could not be used to make complex shape changes (d) could not be used to remove materials in micro/nanoscale |
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Definition
(a) waste of material
(b) time consuming compared to alternative shaping processes, such as casting, powder metallurgy, or forming
(d) could not be used to remove materials in micro/nanoscale |
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Term
| Which of the following material will generate continuous chip during metal machining? (a) low carbon steel (b) SiC (ceramics) (c) hard to machine metals (d) plastics |
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Definition
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Term
| Cutting temperature will increase with which of the following conditions (a) specific energy of cutting (b) specific heat of materials (c) thermal diffusion coefficient (d) depth of cutting |
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Definition
(a) specific energy of cutting
(d) depth of cutting |
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Term
| What are some important design functions of IC packaging? |
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Definition
1) provide electrical connections to external circuits
2) encase chip for protection
3) heat dissipation |
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Term
| The surface of a silicon wafer is thermally oxidized, resulting in a SiO2 film that is "a" thick. If starting thickness of the wafer was "b" what is the final wafer thickness? |
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Definition
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Term
| Which of the three types of chip would be expected in a turning operation conducted at low cutting speeds on a brittle work material? (a) continuous (b) continuous with built-up edge or (c) discontinuous |
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Definition
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Term
| Which of the following processes are used to add layers of various materials in IC fabrication? (a) chemical vapor deposition (b) diffusion (c) ion implantation (d) physical vapor deposition (e) plasma etching (f) thermal oxidation (g) wet etching |
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Definition
(a) chemical vapor deposition
(d) physical vapor deposition
(f) thermal oxidation |
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Term
| In the ion implantation doping process, the concentration peak of the dopant is (a) at the surface (b) below the surface of the substrate |
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Definition
| (b) below the surface of the substrate |
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