Introduction to Mechanical Properties 111

"Introduction to Mechanical Properties" provides a thorough introduction to key mechanical properties, such as tensile strength, hardness, ductility, and impact resistance. This class discusses how shear, compression, and tensile stress impact a material's properties, how force is shown on a stress-strain graph, and common methods manufacturers use to test a material's strength. To make quality products, manufacturers must anticipate how a material responds to shaping and cutting forces and understand how that material will ultimately function once it reaches the customer. Evaluating a material's mechanical and physical properties is the first step to choosing reliable tooling and processing methods. After taking Introduction to Mechanical Properties, users will know more about hardness, ductility, and strength, what materials exhibit these characteristics, and common methods a facility might use to test these qualities.

Class Details

Class Name:
Introduction to Mechanical Properties 111
Difficulty:
Beginner
Number of Lessons:
18

Class Outline

  • Manufacturing Materials
  • Mechanical and Physical Properties
  • The Role of Mechanical Properties
  • Material Properties Review
  • Stress and Strain
  • Elastic Deformation and Plastic Deformation
  • Types of Mechanical Stress
  • Mechanical Stress Review
  • Stress-Strain Graphs
  • Important Mechanical Properties
  • Tensile Strength
  • Tensile Testing
  • Ductility
  • Toughness
  • Impact Strength Tests
  • Hardness
  • Hardness Testing
  • Mechanical Properties Review

Objectives

  • List the four types of manufacturing materials.
  • Define physical properties and mechanical properties.
  • Describe how mechanical properties relate to manufacturing applications.
  • Describe stress and strain.
  • Distinguish between elastic deformation and plastic deformation.
  • Define tensile stress, compressive stress, and shear stress.
  • Describe aspects of a stress-strain graph.
  • List several important mechanical properties.
  • Define tensile testing.
  • Describe ductility.
  • Describe toughness.
  • Describe hardness.
  • Define the major types of hardness tests.

Job Roles

Certifications

Glossary

Vocabulary Term Definition
alloying elements Chemical elements that are added to a metal to modify its properties. Alloying elements, like manganese, chromium, molybdenum, and nickel, are commonly added to steel.
Brinell hardness test A hardness test that measures the diameter of a circle formed by the penetration of a 10 mm steel ball under a fixed load pressure. Brinell hardness tests are often used for forged parts and castings.
brittle Resistant to drawing, stretching, or forming forces. Brittle materials tend to fracture when subjected to these forces.
ceramic A hard, brittle material that can withstand high temperatures and resist corrosion. Ceramics include traditional materials such as brick and clay, as well as advanced ceramics used as abrasives, cutting tools, and electrical components.
Charpy test An impact test that measures the amount of energy a material can absorb. During a Charpy test, a notched sample is supported on both ends and broken by a falling pendulum.
composite A material that is made by combining a binding resin with small filaments of solid material. Composites have the strength of metal, the light weight of plastic, and the hardness of ceramics.
compressive stress A force that attempts to flatten or squeeze a material. Compression strength is the ability to resist compressive stress.
corrosion resistance A material's ability to resist deterioration and chemical breakdown due to surface exposure in a particular environment. Corrosion resistance is an important physical property.
deform To change or distort an object's shape. Deformed objects have permanently lost their original shape.
ductile Able to be drawn, stretched, or formed without fracturing. Ductile is the opposite of brittle.
ductility A material's ability to be drawn, stretched, or formed without breaking. Ductility generally increases as hardness decreases.
elastic deformation A temporary change in the shape of an object or material due to the application of force or stress. When a material experiences elastic deformation, it returns to its original shape once the stress is removed.
elastic limit The maximum stress a material can withstand before being plastically deformed. Elastic limit is also called yield strength.
electrical conductivity A material's ability to act as a medium for conveying electricity. Electrical conductivity depends on the material's structure.
forged Shaped using force to compress and align the metal's internal structure. Forged metals are typically heated during operations.
fracture Complete separation or breaking apart due to force or impact. A fracture occurs more easily in a material that is brittle or has a low tensile strength.
hardness A material's ability to resist indentation or scratching. An increase in hardness generally leads to a decrease in toughness, or ability to withstand fracture.
heat treated Altering a material by heating and cooling in a way that will produce desired properties. Metals are heat treated using the processes like annealing, quenching, and tempering.
impact strength The measure of material's ability to absorb energy from a sudden, sharp blow without fracturing. Impact strength is also known as impact toughness.
impact toughness The measure of material's ability to absorb energy from a sudden, sharp blow without fracturing. Impact toughness is also known as impact strength.
Izod test An impact test that measures the amount of energy a material can absorb. During an Izod test, a notched sample is supported on one end and broken by a swinging pendulum.
load The force applied to an object by another object. Prolonged or heavy loads can cause deformation.
mechanical force A force that attempts to bend, stretch, break, or indent a material. Mechanical forces include compressive, shear, and tensile stress.
mechanical properties A characteristic that describes how a material reacts when subjected to a force that attempts to stretch, compress, bend, dent, scratch, or break it. A material's mechanical properties are usually tested under given loads.
metal A naturally occurring material with high electric and thermal conductivity, density, and strength. Examples of metal include copper, iron, nickel, and lead.
modulus The slope of a stress-strain curve. The shape of the modulus indicates the stiffness or elasticity of a material.
modulus of elasticity A variable that describes the relationship of stress to strain within a material's elastic region. On a stress-strain graph, the modulus of elasticity depicts a material's tendency for temporary deformation.
physical properties A characteristic that describes a material's volumetric, thermal, electrical, and magnetic characteristics. Physical properties describe how a material responds to forces other than mechanical forces.
plastic A polymer material characterized by lightweight, high corrosion resistance, high strength-to-weight ratios, and low melting points. Most plastics are easily shaped and formed.
plastic deformation Permanent deformation of a material due to stress. Plastic deformation occurs after excessive elastic deformation.
Rockwell hardness test A hardness test that measures the degree of penetration into a material caused by a cone-shaped or ball indenter that is applied under a fixed load. A Rockwell hardness test applies two static loads to the material during the test.
shear stress A force that attempts to cause the internal structure of a material to slide against itself. Shear strength is a material's ability to resist shear stress.
specific heat The amount of heat that is required to raise the temperature of a specific amount of material by one degree. Every material has its own unique specific heat.
stiffness The ability of a material to resist bending or stretching. Stiffness is sometimes called rigidity.
strain The physical deformation that occurs in an object when it is under stress. Strain can exist while the object is under stress but can also exist once the force has been removed.
strength A material's ability to resist forces that attempt to break or deform it. A material exhibits tensile, compression, or shear strength, depending on the deforming force.
stress A force that attempts to deform an object. Common forms of stress include compression, shear, and tensile.
stress-strain graph A graph that depicts the relationship between stress and strain and marks the elastic and plastic regions for a given material. Stress-strain graphs are also called stress-strain curves.
tensile strength A material's ability to resist forces that attempt to pull it apart or stretch it. Materials with high tensile strength tend to deform, bend, or stretch before breaking.
tensile stress A force that attempts to pull apart or stretch a material. Tensile strength is a material's ability to resist tensile stress.
tensile test A test that evaluates a material's tensile strength by stretching a specimen until it breaks. Tensile testing is sometimes called tension testing.
tension test A test that evaluates a material's tensile strength by stretching a specimen until it breaks. Tension testing is sometimes called tensile testing.
torsion stress A type of shear stress that attempts to twist a material against itself. Torsion strength is the ability to resist torsion stress.
toughness A material's ability to absorb energy without breaking or fracturing. Toughness is a key property that determines a material's ability to withstand a sudden stress.
yield strength The maximum amount of stress a material can withstand before being permanently deformed. Yield strength is sometimes called a material's elastic limit.