ME 3243 midterm 2

The figure below features diffusion profiles that developed within four separate plain-carbon steel specimens of equivalent geometry after they separately experienced a carburization process. The specimens were prepared such that the scenario of a one-dimensional semi-infinite solid applies as a solution to Fick's 2nd Law of Diffusion. Each part originally contained a uniform distribution of carbon, and each part was processed using the same carburization temperature. In the figure,
corresponds to the surfaces of the steel parts that were exposed to the carbon-rich atmosphere during the diffusion process.

Answer True or False for each of the following statements.

(a) The carburization surface was maintained at 1.00 wt% carbon for each specimen. True or false

(b) Comparing the finished specimens at a depth of 0.75 mm, specimen A features the largest carbon concentration. True or false

(c) Comparing the finished specimens as a whole, specimen A features the lowest overall amount of carbon. True or false

(d) Specimen B experienced a longer carburization time compared to specimen C. True or false

(e) The initial concentration of carbon in each part (prior to carburization) was a little less than 0.25 wt% carbon. True or false

A. True
B. False
C. True
D. False
E. True

The figure below features diffusion profiles that developed within four separate plain-carbon steel specimens of equivalent geometry after they separately experienced a carburization process. The specimens were prepared such that the scenario of a one-dimensional semi-infinite solid applies as a solution to Fick's 2nd Law of Diffusion. Each part originally contained a uniform distribution of carbon, and each part was processed using the same carburization time. In the figure, corresponds to the surfaces of the steel parts that were exposed to the carbon-rich atmosphere during the diffusion process.

Answer True or False for each of the following statements.

(a) The carburization surface was maintained at slightly less than 0.25 wt% carbon for each specimen. True or False

(b) Comparing the finished specimens at a depth of 0.20 mm, specimen A features the lowest carbon concentration. True or False

(c) Comparing the finished specimens as a whole, specimen D features the lowest overall amount of carbon. True or False

(d) Specimen B experienced a higher carburization temperature compared to specimen A. True or False

(e) The initial concentration of carbon in each part (prior to carburization) was approximately 1.00 wt% carbon. True or False

A. False
B. True
C. False
D. True
E. False