Materials Science in Automotive Flashcards
7 cards from real CAE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Materials Science in Automotive flashcards as text
In automotive tribology, what does the Stribeck curve describe?
Answer: Friction coefficient vs. the Hersey number (ηN/P) across lubrication regimes
The Stribeck curve plots friction coefficient against the Hersey number, illustrating the transition from boundary through mixed to hydrodynamic lubrication.
Which alloy designation system is used in the US to classify wrought aluminum alloys for automotive applications?
Answer: AA 1xxx–8xxx series
The Aluminum Association (AA) four-digit system classifies wrought alloys: 1xxx (pure Al), 2xxx (Al-Cu), 6xxx (Al-Mg-Si), 7xxx (Al-Zn), etc.
What failure mechanism causes thermal barrier coatings (TBCs) on automotive turbocharger components to spall?
Answer: Thermally grown oxide (TGO) layer thickening causing interfacial stress
Oxidation of the MCrAlY bond coat grows a TGO layer; as it thickens, mismatch stresses between TGO and topcoat drive interfacial delamination and spalling.
Which property determines the maximum service temperature of a thermoplastic used in under-hood automotive components?
Answer: Heat deflection temperature (HDT) under load
HDT (ASTM D648) measures the temperature at which a material deflects under a specified bending load, directly defining its upper service temperature.
In powder metallurgy (PM) for automotive parts, what is the primary purpose of the sintering step?
Answer: Bond particles by solid-state diffusion to increase strength and density
Sintering at elevated temperature (below melting point) drives atomic diffusion across particle contacts, forming necks and consolidating the part to near-theoretical density.
Which defect in cast aluminum automotive wheels most significantly reduces fatigue life under bending loads?
Answer: Cold shuts at the spoke root radii
Cold shuts are planar defects at spoke roots where two metal fronts meet without fusion, acting as sharp pre-existing cracks in the highest-stress fatigue zone.
What is the role of magnesium in 6xxx series aluminum alloys used for automotive extrusions and body structures?
Answer: Forms Mg2Si precipitates that provide age-hardening response
In 6xxx alloys, Mg and Si combine to form Mg₂Si precipitates during aging, which are the primary strengthening phase.