material fail Flashcards
What is corrosion?
Corrosion is when a refined metal is naturally converted to a more stable form such as its oxide, hydroxide or sulphide state, leading to deterioration of the material.
What typically causes metal corrosion?
Metal corrodes when it reacts with substances like oxygen, hydrogen, electrical current, or dirt and bacteria.
What is the most common type of iron corrosion?
Rust, formed when iron is exposed to oxygen and water.
Define uniform corrosion.
Uniform corrosion is the most common form of corrosion that occurs evenly over large areas of a material’s surface.
What is pitting corrosion?
Pitting corrosion is a localized type of corrosion that forms a corrosion cell, creating a pit that penetrates the material vertically.
What causes crevice corrosion?
Crevice corrosion occurs in areas where oxygen is restricted, resulting from a difference in ion concentration between two areas of metal.
What is galvanic corrosion?
Galvanic corrosion occurs when two different metals in contact are immersed in a common electrolyte, causing the more active metal to corrode faster.
How does intergranular corrosion happen?
Intergranular corrosion occurs when impurities are present at the grain boundaries of an alloy.
What does SCC stand for?
SCC stands for stress corrosion cracking.
What is chemical corrosion?
Chemical corrosion refers to the gradual destruction of a metal’s surface due to reaction with substances in its environment.
Fill in the blank: Stress corrosion occurs when a material exists in a relatively inert environment but corrodes due to _______.
[applied stress]
What is erosion corrosion?
Erosion corrosion is the combined effect of corrosion and erosion caused by the rapid flow of turbulent fluid on a metal surface.
What does corrosion prevention involve?
Corrosion prevention involves measures to protect materials from deterioration due to chemical or electrochemical interactions.
List some methods of corrosion prevention.
- Protective coating
- Metal alloy selection
- Corrosion inhibitors
- Electrochemical control measures
What is deformation in materials engineering?
Deformation refers to material failure due to changes in shape or size from applied forces or temperature changes.
What are the types of deformation?
- Elastic deformation
- Plastic deformation
What is metal fatigue?
Metal fatigue occurs primarily in ductile metals and is a common cause of failure due to repeated stress applications.
What is compressive failure?
Compressive failure is applied to bars and columns leading to shortening under increasing compressive stress.
What are the two major types of fracture?
- Ductile fracture
- Brittle fracture
Describe ductile fracture.
Ductile fracture involves plastic deformation before fracture, allowing the material to stretch.
Describe brittle fracture.
Brittle fracture occurs with negligible plastic deformation, leading to instantaneous crack propagation.
What is necking?
Necking is a type of plastic deformation in ductile materials characterized by a localized reduction in cross-sectional area.
What is cup-and-cone formation?
Cup-and-cone formation is a characteristic of ductile fracture involving necking and the formation of micro-voids that coalesce into a crack.
What is fatigue in engineering material science?
Fatigue is the weakening of a material due to repeated stress applications below the ultimate tensile strength.
