Chapter 6 Mechanical Properties of Metals Flashcards
What are stress and strain
and why are they used instead of load and deformation?
What is elastic behavior in materials?
Elastic behavior is reversible deformation that occurs when a material returns to its original shape after the load is removed. It often shows a linear relationship between stress and strain
What is plastic behavior in materials?
Plastic behavior refers to permanent deformation that occurs when the tensile or compressive stress exceeds the material’s yield strength (σy). This deformation is irreversible.
What is toughness
and how is it measured?
What is ductility
and how is it measured?
What is resilience
and how is it calculated?
What is hardness
and how is it tested?
What is Poisson’s ratio
and how is it defined?
What is Young’s modulus
and what does it measure?
What is the significance of yield strength (σy)?
Yield strength is the maximum stress a material can withstand before permanent deformation occurs. Beyond this point
What is tensile strength (TS)
and how is it determined?
Why do materials show nonlinear elastic behavior?
Some materials
What is the difference between engineering stress and true stress?
Engineering stress is calculated using the original cross-sectional area (<b>σ = F / A₀</b>)
How does temperature affect Young’s modulus?
Young’s modulus generally decreases with increasing temperature because atomic bonds weaken as thermal vibrations increase
What is the modulus of resilience
and why is it important?
What is the difference between ductile and brittle materials?
Ductile materials undergo significant plastic deformation before fracture (%EL ≥ 25%)
What are the two common measures of ductility?
The two common measures of ductility are <b>% Elongation = ((Lf - L₀) / L₀) × 100</b> and <b>% Reduction in Area = ((A₀ - Af) / A₀) × 100</b>
What is the significance of the 0.2% offset yield strength?
The 0.2% offset yield strength is the stress at which a material exhibits 0.2% plastic strain. It is used to determine the yield strength for materials without a clear elastic-to-plastic transition.
What happens during necking in a tensile test?
Necking is a localized reduction in cross-sectional area that occurs after a material reaches its tensile strength. It leads to further strain localization and eventual fracture.
How does interatomic bonding influence stiffness?
Stronger interatomic bonds result in less atomic movement under load
What is the difference between shear stress and normal stress?
Shear stress acts parallel to a surface (<b>τ = Fₛ / A₀</b>)
