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