ME 3010 Test 2

  1. The reaction involving the transformation of one liquid phase into two solid phases upon cooling is called ___.




    B) eutectic reaction
  2. Using the S-N curve provided below, what is the fatigue lifetime at the stress amplitude of 225 MPa?





    E)
  3. ___ Ni-based superalloys will exhibit the best creep resistance.




    C)
  4. A fatigue test was conducted in which the mean stress was 46.2 MPa and the stress amplitude was 219 MPa. The maximum stress level is ___.




    B)
  5. ___ is a standardized test that is widely used in US to measure the impact energy.




    C)
  6. What is the magnitude of the maximum stress that exists at the tip of a surface crack having a radius of curvature of 2.5x10-4 mm and a crack length of 2.5x10-2 mm when a tensile stress of 170 MPa is applied?




    D)
  7. The time_dependent plastic deformation of materials subjected to a constant load (or stress) and temperatures greater than about 0.4Tm(Tm = absolute melting temperature) is termed ___.




    A)
  8. For brittle fracture, cracks are unstable, and the fracture surface has relatively ___ appearance.




    C)
  9. ___ fracture is almost always preferred for the components involoved as (1) during which the presence of plastic deformation gives some warning and (2) more strain energy is required to induce this type of fracture.




    A)
  10. The carbon solubility in ferrite is ___ than that in austenite




    A)
  11. A homogeneous random mixture of chemically distinct elements that form a single phase is a(n) ___.




    B)
  12. Which of the following treatments can improve the fatigue life of a steel component? (All that apply)





    • B)
    • E)
  13. Which of the following treatments can increase the strength of a metallic material? (All that apply)

    A) Converting austenite to martensite
    B) Grain size reduction
    C) Cold working
    D) Converting martensite to tempered martensite
    E) Forming solid solution
    • A)
    • B)
    • C)
    • E)
  14. One limitation of equilibrium phase diagrams is that it does not provide any information of ___. (All that apply)






    • C)
    • F)
  15. Tempering is accomplished by heating a martensitic steel to a temperature, normally between 200-800oC, for a specified time period to allow microstructure/property to change through diffusion.

    True
    -or-
    False
    False
  16. The material is more likely to experience a brittle fracture in service if it has a high ductile-to-brittle transition temperature.

    True
    -or-
    False
    True
  17. Hypoeutectoid steels are usually stronger and harder than hypereutectoid steels if the same heat treatment is applied.

    True
    -or-
    False
    False
  18. Failure of a component in service can occur at an applied stress that is lower than its yield strength if the applied stress is fluctuating.

    True
    -or-
    False
    True
  19. Cast irons contain more carbon than steels.

    True
    -or-
    False
    True
  20. Martensitic transformation is a very slow process.

    True
    -or-
    False
    False
  21. For a hypoeutectoid steel, the proeutectoid ferrite forms at the same time with the eutectoid ferrite because both contain 0.022 wt% C.

    True
    -or-
    False
    False
  22. When the concentration of solute in a solid solution exceeds the solubility limit, a new solid solution or phase that has a composition similar to that of the original solid solution will form.

    True
    -or-
    False
    False
  23. Coarse pearlite forms at temperatures just below the eutectoid temperature, e.g., ~680oC.

    True
    -or-
    False
    True
  24. Tempered martensite is a single-phase microstructure, which shows a good combination of strength and ductility.

    True
    -or-
    False
    False
  25. A steel with 1.0wt% C is a ___.




    A)
Author
85shelbyc
ID
82040
Card Set
ME 3010 Test 2
Description
ME 3010 Test 2
Updated