Materials: Topic 6, Material Properties Flashcards
Tensile properties, hardness, toughness, creep and fatigue are all which types of material properties?
Mechanical
The tensile test is used to measure stress acting on a material against it’s…
Strain
A material under stress will return to it’s original shape until which point of the stress/strain graph?
Maximum Yield Strength Point
If the stress exceeds the yield strength and the materials tensile strength, what is likely to happen?
It will fracture.
The value given to stress divided by strain of a material is called what?
Young’s Modulus (E)
What is the name given to stress and strain when it takes into account changes in cross sectional area and length?
True Stress and True Strain (the graph of which can be found on Topic 6 Slide 26).
What is it called when you exceed the original yield strength and then take away the stress so that you get a new larger maximum yield strength?
Work hardening
What happens when you stretch a polymer past the yield strength?
Plastic deformation
What has a higher tensile strength; thermoplastics or steel?
Steel
Hardness testing machines apply stress to a material using different shape indentors. The Vickers machine has a diamond point at the end. What does the Brinnell machine have?
Hemisphere
What is the toughness of a material?
The ability to withstand an impact load (usually delivered by a pendulum swing in toughness testing).
What is the difference between toughness and hardness?
Hardness is the ability of a material to withstand plastic deformation but toughness is the ability to withstand an impact load.
Some metals go from brittle to ductile at a certain temperature. What is this temperature called?
Transition Temperature
What is the term given to when a material starts going through plastic deformation when going through mechanical stresses?
Creep
90% of all failures in metals is caused by what?
Fatigue
