ENME 421 Midterm 2

7 flashcards · Other · by Dylan Matwe

1. Rank the phases by decreasing strength

   Martensite T Martensite Bainite Fine Pearlite Coarse Pearlite spheroidite

2. List the 3 strengthening mechanism

   Reduce Grain Size Solid-Solution Strengthening Strain Hardening

3. Explain how reducing the grain size increases the strength of a material

   — increase grain boundary area — more barriers to dislocation motion —increase yield strength, tensile strength & hardness

4. Explain how solid-Solution Strengthening increases the strength of a material

   — Alloying with impurity atoms that go into either substitutional or interstitial solid solution to strengthen and harden metals.

5. Explain Strain Hardening

   — Plastically deforming metals at room temp. to makes them harder and stronger —Dislocation density increases with increasing deformation

6. Where is this on the Fe graph, and what's it made of

   It's the first one, made of austenite

7. Where is this on the Fe graph, and what's it made of

   It's the second one It's "Ledeburite", made of austenite and Ferrite