Material Testing and Properties Flashcards
compressive strength
ability to withstand crushing forces
tensile strength
ability to withstand stretching forces
bending strength
ability to withstand bending forces
shear strength
ability to withstand sliding forces on a parallel plane to the material
torsional strength
ability to withstand twisting forces from applied torque or torsion
hardness
ability to withstand abrasion, indentation and cutting
toughness
ability to absorb sudden shocks without fracturing
plasticity
ability to be permanently deformed and retain the new shape
ductility
ability to be drawn into a wire under a tension
malleability
ability to withstand deformation and compression without cracking
elasticty
ability to be deformed and then return to the original shape when the force is removed
density
the mass per unit volume
fusibility
how well a material can be converted to a liquid state
magnestism
a materials ability to interact with or create a magnetic field
corrosion/degradation resistance
ability to withstand an attach from the environment or decay
electrical conductivity
how well a current can travel through a material (its resistance)
thermal conductivity
how well heat is transferred through a material
thermal expansion
how a materials volume increases as it is heated
Opaque
a material which blocks all light travelling through it
translucent
a material which blocks some of the light travelling through it
transparent
a material that allows all light to pass through it
workshop test for toughness
lock a test piece in a vice and strike it with a hammer compare if it fractures or deforms. a tougher material will deform and absorb the blow
workshop test for hardness
use a hammer and dot punch to indent the material
the harder the material the smaller the diameter of the indentationn
workshop test for malleability and ductility
lock a test piece in a vice
bend it through 90 degrees or until it fractures
cracking on the inside of the bend is a lack of malleability
cracking on the outside is a lack of ductility
workshop test for corrosion
place test piece in an exposed area or in a corrosive chemical and leave for an extended period
compare the relative break down of each material
workshop test for conductivity
use a multimeter and set the probes to either end of the material
test the resistance of the material and compare it to other samples
higher resistance is a lower conductivity
workshop test for thermal conductivity
use a bunsen burner to heat one end of a material
set up a thermometer on the other end
time how long it takes for the thermometer to increase in temperature
Industrial test for tensile strength
use a tensometer machine
the test piece is gripped at both ends
on clamp is attached to a worm drive which pulls it backwards
the load, extension and breaking point are recorded and plotted on a stress/strain graph
industrial test for toughness
Izod impact test
a notched test piece is held vertically in a vice
a pendulum is released from a fixed height and strikes the test piece
the rebound height is recorded
tougher materials will absorb the blow and the rebound height is small
brittle materials do not absorb the blow and the rebound height is larger
Industrial test for malleability/ductility
use a bend test
bending machine uses a mandrel or plunger to bend a test piece through a set angle the cracks are observed and compared
cracks on the outside of the bend indicate a lack of ductility
cracks on the inside of the bend indicate a lack of malleability
Industrial test for corrosion
very similar to workshop testing but done in a lab environment with far greater control of the conditions of corrosion
Industrial test for thermal conductivity
heat flow meter
material is placed between two temperature controlled plates
temperature is increased at a constant rate
thermal sensors on the surface of the material measure the temperature across the material
NDT(non-destructive testing )
testing materials without damaging or destroying them
it is used to find defects in materials
X-ray NDT
X-ray beam passes through a material and is absorbed different in defects than in the nominal material allowing an imagine to be generated of the tiny imperfections of the material
ultrasonic NDT
sound waves are pushed through a material
where they interact with a defect they distort allowing defects to be identified
industrial test for hardness (vickers pyramid)
for very hard materials
a diamond pyramid is loaded and indents into a material
a microscope measures the indentation and the extent of indentation determines the hardness of the material
the diamond is used as it will not deform
Industrial test for hardness (Rockwell)
a diamond indenter is preloaded to break through the surface of a material
additional load is applied over a dwell time
the distance between the indentation of the preload and the applied load is measured
Industrial test for hardness (Brinell)
a hardened steel ball is forced into a material the diameter of the indent is recorded and compared
a wider indent is a less hard material
