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 primary reason titanium alloys are used in aircraft engine compressor blades?
Answer: High strength-to-weight ratio and heat resistance
Titanium alloys offer an exceptional strength-to-weight ratio combined with good heat resistance, making them ideal for compressor blades.
Which heat treatment process is used to relieve internal stresses in metal without significantly changing its hardness?
Answer: Stress relieving
Stress relieving heats metal to a temperature below the transformation range and cools it slowly to reduce residual stresses without major hardness changes.
What does the term 'fatigue strength' refer to in aircraft materials?
Answer: Stress level a material can withstand for an infinite number of cycles
Fatigue strength is the stress level below which a material can endure an indefinitely large number of loading cycles without failing.
Which aluminum series alloy is most commonly used for aircraft structural skins due to its balanced strength and corrosion resistance?
Answer: 7xxx series
7xxx series aluminum alloys (alloyed with zinc) offer the highest strength of aluminum alloys and are widely used in aircraft structural applications.
What is galvanic corrosion and when is it most likely to occur in aircraft?
Answer: Electrochemical corrosion when dissimilar metals contact in the presence of an electrolyte
Galvanic corrosion occurs when dissimilar metals are in electrical contact in the presence of an electrolyte, creating a current that corrodes the less noble metal.
What property is measured by the Rockwell hardness test?
Answer: Resistance to plastic deformation under indentation
The Rockwell hardness test measures a material's resistance to permanent indentation under a specific load, indicating surface hardness.
Which composite material configuration provides the highest stiffness in a specific direction?
Answer: Unidirectional laminate with all fibers aligned 0°
A unidirectional 0° laminate concentrates all fiber reinforcement in one direction, maximizing stiffness and strength along that axis.