6.0- General Flashcards
Give the definition for Hardness.
Resist penetration, wear or cutting action.
Give the definition for Strength.
Resist stress without breaking.
Give the definition for Elasticity.
Return to original size and shape after deformation.
Give the definition for Plasticity.
Property that allows it to be reshaped.
Give the definition for Ductility.
Drawn into thinner sections without breaking.
Give the definition for Malleability.
Stretched or shaped without breaking.
Give the definition for Toughness.
Deformed without breaking.
Give the definition for Brittleness.
To deform or break when stress and force is applied.
What is stress defined as?
Force per unit area.
What are the SI units for stress?
N/M² or Pascals.
What is the Imperial measure for stress?
psi
Give the definition for Tensile stress.
To stretch.
Give the definition for Compressive stress.
To squish.
Give the definition for Shear stress.
To break.
What are the Combined Stresses. (2 combinations)
1) Tensile+ shearing
2) Compressive+ shearing.
What is Simple stress?
Just one of the stresses acting.
What is Unit strain?
Deformation of shape due to application of load divided by original dimension.
What is Poissons ratio?
Ratio of lateral to longitudinal strain to a material when subject to uniform longitudinal stress. E.g. when you stretch it how much thinner does it become.
What is the poisson ratio values for steel?
0.30
What is the poisson ratio values for wrought iron?
0.28
What is the poisson ratio values for cast iron?
0.27
What is the poisson ratio values for brass?
0.34
Give the definition for metallic.
Contains metal or metal alloys.
Give the definition for ferrous.
Contains iron.
Give the definition for elastic limit.
Item can return to its original shape after acting force is removed.
What is the elastic limit of steel also known as?
The proportional limit.
Give the definition for yield strength?
Maximum stress that can be applied without permanent deformation.
Give the definition for ultimate tensile strength?
Maximum stress that can be applied without breaking.
What is the modulus of elasticity?
Ratio of stress to strain within the proportional limit of material in tension or compression.
In a phase diagram what are the axis always labelled as?
y- temp
x- percentage of alloy.
For airframes what density of metal is normally used?
Below 5 Kg/dm³.
What are the three most important metals in aircraft structure?
1) Aluminium and alloys
2) Titanium and alloys
3) Magnesium and alloys
What is the density of aluminium?
2.7Kg/dm³.
What is the density of titanium?
4.5Kg/dm³.
What is the density of magnesium?
1.74Kg/dm³.
Where can metal densities between 7.85 and 9.5 Kg/dm³ be used?
Aircraft structure where high weights or higher strengths are needed.
What is the definition of a crystal?
A rigid body where all particles form in a repeating pattern.
How many atoms does Body centred cubic have (BCC)?
9
How many atoms does a face centred cubic have (FCC)?
14
What metals are examples of FCC? (6 examples)
Aluminium, copper, gold, nickel, silver and iron.
What metal is a bcc below 910°c and fcc above 910°c?
Iron.
How many atoms in hexagonal close packed (HCP)?
17.
What metals are HCP? (4 examples)
Cobalt, magnesium, titanium, zinc
What are the different characteristics considered in material selection?
Quality, cost, maintenance, repair
