Materials and Processing Exam 2 (Chap. 3 & 6)
what elements are traditionally alloyed with copper to form (a) bronze (b) brass
(a) tin (b) zinc
what are some important applications of nickel
- alloying ingredient in steel - plating of steel to resist corrosion - Ni-based alloys: high temperature performance and corrosion resistance
what is the range of carbon percentages that defines an iron-carbon alloy as a steel
0.02% -2.1% carbon
plain carbon steels are designated in the AISI code system by
10XX
what is the range of carbon percentages that defines an iron-carbon alloy as a iron
2.1% - 5% carbon
while cold forging is done at room temperatures, hot forging occurs at
200 to 3,000 degrees
tensile testing is not appropriate for hard brittle materials such as ceramics. what is the test commonly used to determine the strength properties of such materials
3-point bending test
total debinding and sintering time can range
8 to 24 hours
parts produced by injection molding have densities in the range of
95% or more
How is the shear modulus of elasticity G related to the tensile modulus of elasticity E, on average.
G is approximately equals to 0.4E
how is shear strength S related to tensile strength TS, on average
S is approximately equals to 0.7 (TS)
what is an alloy
a metal composed of two or more elements with at least one element being metallic
evaporative foam casting is used to cast
a variety of ferrous and nonferrous alloys
the device used to increase injection pressure is called
accumulator
identify some of the mechanisms by which the alloying elements other than carbon strengthen steel
all of the alloying elements other than carbon strengthen steel by solid solution increase hardenability during heat treatment and improves hot hardness
three basic methods for strengthening metals
alloying cold working heat treatment
the bayer process is associated with the production of what metal
aluminum
which has the highest hardness
alunima ceramic
what is an intermediate phase in the context of alloys
an alloy formed when the solubility limit of the base metal in the mixture is exceeded and the new phase is formed
what is a solid solution in the context of alloys
an alloy in which one element is dissolved in another to form a single-phase structure with a metallic element as the solvent
parts produced by powder metallurgy
are of net or near net shape
parts in a "green state" are
at minimum strength
as temperature is increased to slightly about 912 degrees Celsius (1674 Fahrenheit), pure iron transforms into
austenite
what is the complicating factor that occurs in a compression test that might be considered analogues to necking in tensile test
barreling
from which of the following ore is aluminum derived
bauxite
Forging as a process is closely related to
blacksmithing
wha tis hardness and how is it generally tested
by pressing a hard object (sphere or diamond point) into the test material and measuring the size (depth area) of the indentation
which element is the most important alloying ingredient in steel
carbon
the transverse rupture strength is a property usually associated with which material types
ceramics
what is the predominant alloying element in all stainless steels
chromium
which elements are most commonly associated with stainless steel
chromium nickel
what are the three metals used as the principal constituent in superalloys
cobalt iron nickel
name the important refractory metal
columbium (Cb), molybdenum (Mo), tantalum (Ta), and tungsten (W)
the foam method also eliminates the need for
copes and drags
which of the following metals is noted for its good electrical conductivity q
copper
name the four principal nobel metals
copper gold platinum silver
traditional brass is an alloy of which of the following metallic elements
copper and zinc
what is the dilemma between design and manufacturing in terms of mechanical properties
desirable mechanical properties to designer usually makes it difficult to manufacture
what is viscoelasticity as a material property
determines the strain a material experiences when subjected to combination of stress and temperature over time
which material has the highest modulus of elasticity
diamond
the alloy's melting temperature will dictate the
die and core draft
identify some important applications of zinc
die casting galvanized steel alloyed with Cu to form brass
why are different hardness tests and scales required
difference in hardness among different materials
die cores are placed in the
either the ejector or cover half of the mold
the "movable" platen holds the
ejector half of the mold
types of stress strain relationship that best describes the behavior of metals at temperature above their respective recrystallization points
elastic and perfectly plastic
hooke's law defines which region of the stress strain relationship for engineering materials
elastic region
the two most important processes in steelmaking are
electric arc furnace basic oxygen furnace
difference between engineering and true stress
engineering is force divided by original area true stress is force divided by instantaneous area
when dealing with strain in tensile test which is of higher value
engineering strain
define tensile strength of material
engineering stress at the point in which the applied load reaches its maximum value
hooke's law
engineering stress is equals modulus of elasticity times the engineering strain (S=Ee)
"flash" refers to
excess metal flowing out of a die
the predominant phase in the iron-carbon alloy system for a composition with 99% iron at room temperature is
ferrite
what are the two major groups of metals
ferrous: metals based on iron nonferrous: all other metals
a "bag" refers to a
flexible mold
what is the defining characteristic of a Newtonian fluid
fluid wiht viscosity being a constant property of a given fluid
forging lubricants are
graphite based
which of the following is the most important cast iron commercially
gray cast iron
powders produced by mechanical method means are
hard and brittle
the principal ore used in production of iron and steel is
hematite
what is the most important engineering property of copper that determines most of its application
high electrical conductivity
Which of the following properties or characteristics do not apply to metals
high electrical resistivity ionic bonding
what are some of the general properties that distinguish metals from ceramics and polymers
high stiffness and strength toughness good electrical conductivity good thermal conductivity
what are the noteworthy properties of titanium
high strength-to-weight ratio corrosion resitances high temperature strength
the common die material is
hot work tool steel
an endothermic atmosphere includes
hydrogen
a steel with 1.0% carbon is know as
hypereutectoid
another name for closed die forging is
impression forging
the strength and hardness of steel increases as carbon content
increases
an alloy is a metal composed of two or more elements, at least one of which is metallic. the two main categories of alloys are
intermediate phases solide solutions
the alternate name for the "lost wax" casting process is
investment casting
the most common powders used in powder metallurgy are
iron and steel
water atomized particles are
irregular
the mechanical properties of a casting is improved by
isostatic pressing
the copper-nickel system is a simple alloy system, as indicated by its phase diagram. why is it so simple?
it is a solid solution alloy throughout its entire range of composition below the solidus with no intermediate solid phases
the shear strength of a metal is usually what when compared with tensile strength
less than its tensile strength
what are some of the noteworthy properties of magnesium
lightest structural metal propensity to oxidized good strength-to-weight ratio when alloyed
identify some of the properties for which aluminum is noted
low density high electrical and thermal conductivity formability excellent corrosion resistance good strength-to-weight ratio
"hot chamber" die casting machines are used for alloys with
low melting temperatures
which of the following metals has the lowest density
magnesium
hot die and isothermal forging is used on
materials with narrow forging ranges
definition of ultimate tensile strength
maximum load divided by the original area
the term "castability" is most related to a metal's
melting temperature
what are nobel metals
metals that are chemically inactive
high-speed steels are used in cutting tools for machining. which alloying elements are used in the highest portion in high-speed steel
molybdenum tungsten
types of stress strain relationship that best describes the behavior of brittle materials such as ceramics and thermosetting plastics
perfectly elastic
iron tapped from the blast furnace is
pig iron
permanent mold casting requires cores that are made of
plaster, metal, and sand
which of the following metals has highest density
platinum
metal flow in open-die forging is
practically unlimited
define viscosity of fluid
resistance to flow that is characteristic of a given fluid
hardness is best defined as
resistance to permanent indentation
"cold isostatic pressing" takes place at
room temperature
the least expensive method of expendable mold/reusable pattern casting uses the
sand mold
which one of the following is the source of most commercially produced magnesium
sea water
die casting is used mainly to produce
smaller non-ferrous metal parts
what important alloy is formed from lead and tin
solder
the principal strengthening mechanism in high-strength low-alloy (HSLA) steels is
solid solution alloying
the flow curve describes the property of metals known as
strain hardening
the plastic region of the stress-strain curve for a metal is characterized by proportional relationship between
stress and strain
what are the three types of static stresses which materials are subjected to
tensil compressive shear
how does the change in cross-sectional area of a test specimen in a compression test differ from its counterpart in a tensile test specimen
test specimen cross-sectional area increases as the test progresses whereas in tensile test it decreases
in true-centrifugal casting, the inside diameter of the cast part is determined by
the amount of molten metal poured into the die
define refractory
the capability to withstand high temperature service
a eutectic alloy is which of the following
the composition in an alloy system for which the solidus and liquidus are at the same temperature the composition in an alloy system that has the lowest melting point
why cannot a direct conversion be made between the ductility measures of elongation and reduction in area using the assumption of constant volume?
the necking that occurs in metallic test specimens the associated non uniform effect on the elongation area reduction
define yield strength of material
the point in which the material begins to plastically deform
the inverse lever rule is used to determine what in a binary phase diagram
the proportions of each phase present at a given temprature
define the recrystallization temperature for a metal
the temperature at which the formation of new strain-free grain occurs
the primary difference between hot die forging and isothermal forging is
the temperature of the workpiece
what is so special about superalloys
they have high strength and resistance to corrosion and oxidation at elevated temperature
the shear strength of a metal is commonly determined in which test
torsion test
T/F: binary phase diagram is a phase diagram indicating the phases of two metallic elements as a function of composition and temperature at atmospheric pressure
true
T/F: most hardness tests involve pressing a hard object into the surface of a test specimen and measuring the resulting indentation or its effect
true
when dealing with stress in tensile test which is of higher value
true stress
A characteristic of a casting is its
uniform grain structure
under what circumstances does the strength coefficient have the same value as the yield strength
when the material is elastic and perfectly plastic
what is work hardening (strain hardening)
when the metal becomes stronger as train increases
modulus of elasticity is known as
young's modulus
galvanized steel is steel that has been coated with
zinc
the best castable alloys are
zinc
which metal has the lowest melting point
zinc
which of the following is not a common alloying ingredient in steel
zinc
"hot chamber" die casting is used for
zinc parts
