1.1 Material Selection Part 3 Flashcards
What are the mechanical properties of a material?
Strength, Elasticity, Plasticity, Toughness, Hardness, Durability & Brittleness.
What happens when too great of a force is applied to a material?
It will deform.
What are the 2 types of deformation?
Temporary (Elastic)
Permanent (Plastic)
What is strength?
A materials direct ability to withstand force without breaking or permanently breaking.
What are the 5 different types of material strength? Explain them.
Tensile Strength
Materials ability to resist pulling/stretching forces
Compressive Strength
Materials ability to withstand pushing forces trying to crush or compress it.
Bending Strength
Materials ability to withstand a force trying to bend it.
Shear Force Strength
Materials ability to withstand a sliding force on both sides of the material meant to split it.
Torsional Force Strength
Materials ability to resist the torque(twisting) force applied to it.
What is elasticity in a material?
This is the materials ability to flex, bend and deform and return to its original form without permanant deformation.
What is plasticity of a material?
A materials ability to change shape permanently as the result of a force applied on it without breaking or cracking.
Sometimes plasticity increases once a material is heated up.
What are the 2 types of plasticity in materials?
Ductility and Malleability
Describe Malleability
The degree to which materials can be deformed in all directions as a compression force caused by impacts such as hammering, pressing, rolling without it breaking or cracking.
Describe Ductility
Materials ability to be drawn into a thinner and longer. Ductile deformation happens as a result of tensile force.
Describe toughness of a material.
Materials ability to withstand sudden shocks or blows from a force.
What is the test used for testing the toughness of a material and what do the results tell us?
A pendulum hammer swings from a set height and hits the material which has a 45° notch cut into it, once the material is hit, it breaks and the hammer keeps going. Depending on how far the hammer will swing past the vice will depend on how much force the material absorbed. The more it absorbed the shorter the distance will be.
What is hardness in a material?
Materials ability to resist indentation which is the result of an impact as well as resistant to scratching.
What is the most common scratch test?
Moh’s scale has a ranking of 1-10, and each material can scratch the one before it(rank 8 scratches rank 6), Diamonds is rated as a 10.
What is the general method for an indentation test?
A hard object is forced onto the surface of a material. Using the surface area of the indentation or the depth of it we can see how hard the material is.
What are the 3 indentation tests, what do they involve?
Brinell Test (Using a hard steel ball)
Vickers Test(using a small pyramid-shaped diamond tool)
Rockwell test(Either steel ball or diamond cone)
How does durability affect a material?
It will determine how much wear & tear and deterioration it can withstand due to weathering.
What causes the weathering of a material?
Metals corroded away, Plastics decay.
This causes it to weaken mechanically or its shape may deform.
How does brittleness affect a material?
It makes it have worse plasticity as brittleness is the opposite of plasticity.
This causes materials to snap/break or shatter before they can deform.
Usually they contain high compressive strength but low tensile strength.
