HIGH RESOLUTION SCANNING AUGER MICROSCOPIC INVESTIGATION OF INTERGRANULAR FRACTURE IN AS-QUENCHED Fe-12Mn
Previous research in this laboratory led to the conclusion that the low temperature intergranular fracture mode in Fe-Mn alloys is microstructurally determined, and does not require metalloid segregation or other chemical contamination. That conclusion was tested in the present investigation, which used high resolution scanning Auger microscopy to study the intergranular fracture surfaces. The fracture mode at liquid nitrogen temperature was found to be intergranular fracture whenever the alloy was quenched from the austenite field, irrespective of the austenization time or temperature. High resolution chemical analyses of the intergranular fracture surfaces failed to reveal any consistent segregation of P, S, 0, or N. The occasional appearance of sulfur or oxygen on the fracture surface was found to be due to a low density precipitation of MnS and MnO{sub 2} along the prior austenite grain boundaries. Excepting these dispersed precipitates, there was no evidence of manganese enrichment of the prior austenite grain boundaries. A slight segregation of carbon was found along the grain boundaries, but does not appear to be implicated in the tendency toward intergranular fracture. The present results hence reinforce the conclusion that the low temperature intergranular fracture of Fe-12Mn is microstructurally determined.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- Materials Sciences Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 1077848
- Report Number(s):
- LBL-11629
- Resource Relation:
- Conference: Annual Meeting of the Metallurgical Society/AIME Societies, Chicago, IL, February 22-26, 1981
- Country of Publication:
- United States
- Language:
- English
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