Materials Science: Dislocations and Strengthening

What is a dislocation in the context of materials science?

When was the existence of dislocations directly observed?

What are the two primary types of dislocations?

Which of the following best describes an edge dislocation?

What is the motion of a screw dislocation?

What is the term used to describe permanent deformation of materials by dislocation motion?

Which of the following is true about a slip system?

What is a slip plane?

What is slip direction?

What does grain size reduction do to a material's strength?

According to the Hall-Petch Equation, what happens as grain size decreases?

Which of the following strengthening mechanisms involves adding alloying elements to a metal?

What type of impurity atom replaces a host atom in solid solution strengthening?

What type of impurity atoms fill the gaps between atoms in solid solution strengthening?

Which strengthening mechanism involves the metal becoming stronger after plastic deformation?

What is the effect of strain hardening on a metal?

What is percent cold work (PCW) a measure of?

Which of the following is the formula for percent cold work?

What is recovery in the context of metal deformation?

What occurs during recrystallization?

What happens during grain growth?

What is the primary role of grain boundaries in strengthening metals?

Which technique is most effective for strengthening polycrystalline materials?

What happens when metals undergo extensive plastic deformation at low temperatures?

Which of the following is NOT a stage in the recovery, recrystallization, and grain growth process?

What are polymers?

What are the repeating units in polymers called?

Which of the following is a natural polymer?

Which polymer is used to make plastic bags?

Which polymer is known for its elasticity?

Which polymer is commonly used to make pipes?

Which polymer is lightweight, strong, and used in packaging?

Which of the following is a synthetic polymer?

What is the main monomer used to make polystyrene?

What is cross-linking in polymers?

What is the main feature of biodegradable polymers?

Which polymer is used for making bottles?

What is Bakelite used for?

What is the process called when monomers join without producing any byproduct?

What property allows polymers to stretch and return to their original shape?

Which polymer is used for making bulletproof vests?

What property of polymers makes them suitable for use as insulators in electrical applications?

What is a key factor affecting the strength of a polymer?

Which property of polymers is enhanced by cross-linking?

Why are polymers like polystyrene used for insulation?

What does the molecular mass of a polymer represent?

Which term is used to describe the average molecular mass of polymers weighted by the number of molecules?

The Polydispersity index (PDI) is calculated using which formula?

What is the value of the Polydispersity index (PDI) of natural polymers?

Which of the following accurately describes weight-average molecular mass (MW)?

Why is it important to study failure?

What is one of the three usual causes of failure?

Which type of fracture is usually preferred?

Why is ductile fracture preferred over brittle fracture?

Which type of environment-assisted fatigue failure involves fluctuating thermal stresses?

What are the three usual causes of failure?

Which type of fracture occurs with very little accompanying plastic deformation?

What is the main characteristic of brittle fracture?

What type of failure is the single largest cause of failure in metals?

Which testing techniques are used to measure impact energy?

What is fatigue?

What is the definition of creep?

Which phase of creep involves a constant creep rate?

What type of creep occurs at elevated temperatures due to fluctuating stresses?

Which type of crack is more stable, requiring an increase in applied stress to propagate?