Material Selection & Properties Flashcards
7 cards from real AM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Material Selection & Properties flashcards as text
What is the function of an alclad coating on aluminum sheet?
Answer: Provide sacrificial corrosion protection to the core alloy
Alclad is a thin layer of pure aluminum bonded to a stronger aluminum alloy core; the pure aluminum corrodes preferentially, protecting the structural core.
Which non-destructive testing method is best suited for detecting subsurface cracks in non-ferrous metals?
Answer: Eddy current inspection
Eddy current inspection can detect both surface and subsurface discontinuities in conductive non-ferrous materials without requiring magnetic properties.
What does a material's modulus of elasticity (Young's modulus) describe?
Answer: Stiffness—ratio of stress to strain in the elastic range
Young's modulus is the ratio of applied stress to resulting elastic strain, quantifying a material's stiffness or resistance to elastic deformation.
Which type of stainless steel is most commonly used for aircraft exhaust components due to its high-temperature oxidation resistance?
Answer: Austenitic stainless steel
Austenitic stainless steels (300 series) maintain strength and resist oxidation at elevated temperatures, making them suitable for exhaust systems.
What is the purpose of shot peening an aircraft component?
Answer: Introduce compressive residual stresses to improve fatigue life
Shot peening bombards the surface with small steel or glass beads, inducing compressive residual stresses that retard fatigue crack initiation.
Carbon fiber reinforced polymer (CFRP) composites are anisotropic. What does this mean for maintenance?
Answer: Their mechanical properties differ depending on direction of load application
Anisotropic materials have direction-dependent properties, so CFRP repairs must account for ply orientation and load direction to restore structural integrity.
What is intergranular corrosion and which aluminum alloy family is most susceptible?
Answer: Corrosion along grain boundaries; 2xxx series
Intergranular corrosion attacks grain boundaries preferentially; 2xxx series (copper-alloyed) aluminum alloys are particularly susceptible when improperly heat-treated.