The GATE Grind

GATE 2021 MT – Question 15

Manufacturing Processes · Metal casting · 1 mark · Multiple choice

Single-crystal nickel-based superalloy turbine blades for aero-engines are manufactured using ______.

  1. Investment casting
  2. Die casting
  3. Squeeze casting
  4. Directional solidification

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Show answer and explanation

Correct answer: (D) Directional solidification

Explanation

Controlled directional solidification, combined with crystal selection or seeding, grows one crystal through the blade and removes high-temperature grain-boundary weakness.

Therefore **D** is the distinctive process for the stated single-crystal requirement.