Fundamentals of materials science part 2 Flashcards

1
Q

materials with mechanical properties dependent of loading rate and with viscous and elastic behavior are what?

A

viscoelastic

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2
Q

Materials with mechanical properties independent of loading rate are what?

A

elastic

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3
Q

the resistance of a fluid to flow and is equal to the shear stress/shear strain rate is what?

A

viscosity

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4
Q

what is hardness?

A

resistance to permanent surface indentation or penetration

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5
Q

What is friction?

A

the resistance between contracting bodies when one moves relative to another

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6
Q

What is wear?

A

is loss of material resulting from removal and relocation of materials through the contract of two or more materials

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7
Q

Adhesive wear

A

formation and disruption of microjunctions

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8
Q

corrosive wear

A

secondary to physical removal of protective layer and it is related to the chemical activity of the wear surfaces

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9
Q

surface fatigue wear

A

free particles with small areas of contact contribute to high localized stress and produce surface cracks

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10
Q

abrasive wear

A

involves a harder material cutting into a softer material

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11
Q

what are colloids

A

substances that consist of two or more phases, with the units of at least one of the phases having a dimension slightly greater than simple molecular size.
Highly dispersed system of the fine dispersions
eg. gels, films, emulsion, foams

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12
Q

what is a sol

A

a solution, that is made up of colloidal particles dispersed in a liquid

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13
Q

what is a gel

A

when suitable amount of chemicals to the sol that the solution becomes jelly like

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14
Q

adsorption

A

a liquid or gas adheres to the surface of a solid or liquid firmly by attachment of molecules, decreases their surface free energy

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15
Q

absorption

A

the substances diffuses into the solid material by a diffusion process, and the process is characterized by concentration of molecules at the surface

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16
Q

soprtion

A

when adsorption and absorption exist at the same time and it is unknown which one predominates

17
Q

what is wetting

A

the tendency to spread on the surface of the solid

18
Q

the eye can distinguish differences in how parameters of color?

A

3, dominant wavelength, luminous reflectance, and excitation purity

19
Q

what is hue

A

the colors between violet and red on the wavelength spectrum. eg: green, yellow, orange light

20
Q

value

A

the quality of lightness or darkness. That is black is a dark value or low value. White is a light value or high value

21
Q

chroma

A

the quality of a colors purity, intensity or saturation

22
Q

what do rough surfaces appear lighter than smooth surfaces?

A

because more white light is reflected back on rough surfaces and dilutes the color

23
Q

what is metamerism

A

colors that have the same value under a particular light source but under another source they look different

24
Q

flourescence

A

the emission of luminous energy by a material when a beam of light is shone on it

25
opactiy
a property of materials that prevents the passage of light, when all colors are absorbed it is black and when they are all reflected it is white
26
translucency
a property of substance that permits the passage of light but disperses the light, so objects cannot be seen through the material
27
opalescent
materials that are able to scatter shorter wavelengths of light. eg. enamel
28
what is heat of fusion
the heat in calories or joules, required to convert 1 gram of material from solid to liquid state at the melting temperature
29
thermal conductivity
is the quality of heat in calories or joules, per second passing through a body 1 cm thick with a cross-section of 1cm squared when the temperature difference is 1 degree celcius
30
specific heat
the quantity of heat needed to raise the temperature of 1 gram of the substance 1 degree celcius
31
thermal expansion
the measure of change in length of material for a 1 degree change in temperature
32
dielectric
a material that provides electrical insulation
33
electromotive force
the voltage developed by any source of electrical energy
34
galvanism
results from a difference in potential between dissimilar fillings in opposing or adjacent teeth, resulting in current running through the pulp when the two teeth touches due to a short circut
35
electrochemical corrosion
corrosion that is accompanied by a flow of electrons between cathodic and anodic areas on metallic surfaces
36
zeta-potential
the potential difference existing between the surface of a solid particle immersed in conducting liquid and the bulk of the liquid