Intellectual Merits MET DMR-0348818, Seetharaman, Carnegie Mellon University

Motivation: The structure and properties of steel parts for various applications, depend on the rates of and manner in which a number processes occur at high temperatures, such as flow of molten steel, reactions between molten steel and its container, slag, and atmosphere, solidification and solid state phase transformations. Since all these kinetic processes occur at high temperatures, they are somewhat difficult to study through classical metallographic tools such as optical or electron microscopy.

Goals: This program aims to utilize and enhance current capabilities to quantify high temperature metallurgical phenomena through direct observations. A high temperature confocal scanning laser microscope and x-ray fluoroscopy

Initial structure: Electron microscopy

Observation of structural changes during thermal treatment: High

temperature confocal microscopy

Final structure: Optical microscopy

508ºC

949ºC

50 μm

551ºC

250ºC

Example: increasing the understanding of thermal processing by following the evolution of microstructure through the use of multiple microscopy techniques

Broader Impacts

Outreach: A materials science module was developed and used for a two day SWE activity for female middle and high school students. The middle-school activities included: (i) casting miniature metal statues and characterizing cast structures, (ii) investigating temperature sensitive mechanical properties of polymers and (iii) introducing the phenomenon of superconductivity. The high school activities involved developing materials for a “rocket to be launched to space”. Approximately 50 students participated in each of the two age groups.

Education: A web based module is being developed that shows CSLM movies of solidification and phase transformation phenomena for Fe-based alloys. The module will have the appearance shown below to the left. CSLM movies have been develop for a Fe-C alloys and examples are shown, in the figures to the right. The images show -ferrite platelet precipitation from a -matrix upon cooling.

MET DMR-0348818, Seetharaman, Carnegie Mellon University

Cooling

Composition:

File Tools

Conditions:

Window

wt%Fe:Time: 1:15:06 Temp: 1528 C

66.8um

Time: 1:15:06 Temp: 1528 C

66.8um66.8um

Help

Phases:-ferrite, liquid

Solidification Module Fe-C

wt%C:

Heatingx

99.94 0.06

Tstart [oC]:

Cooling rate [oC/sec]:

1540

3

?

What’s this?

Shortcut to Tutorial

(a)

(c)

(b)

(d)

15 m 15 m

15 m 15 m

0 s 2 s

6 s4 s