Strain measurements in thermally grown alumina scales using ruby fluorescence

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:434919

Veal, B W; Natesan, K; Koshelev, I; Grimsditch, M ^[1]; Hou, P Y ^[2]

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1. Argonne National Lab., IL (United States)
2. Lawrence Berkeley Lab., CA (United States)

We have measured strains in alumina scales thermally grown on Fe-Cr- Al alloys by exploiting the strain dependence of the ruby luminescence line. Measurements were done on Fe-5Cr-28Al and Fe-18Cr-10Al (at.%, bal. Fe) oxidized between 300-1300 C with periodic cycling to room temperature. Significantly different levels of strain buildup were observed in scales on these alloys. Results on similar alloys containing a dilute reactive element (Zr or Hf) are also presented. We observe that scales on alloys containing a reactive element (RE) can support higher strains than scales on RE-free alloys. With the luminescence technique, strain relief associated with spallation thresholds is readily observed. In early stage oxidation, the evolution of transition phases is monitored using Raman and fluorescence spectroscopies. The fluorescence technique also provides a sensitive probe of early stage formation of {alpha}-Al{sub 2}O{sub 3}. It appears that, in presence of Cr{sub 2}O{sub 3} or Fe{sub 2}O{sub 3}, the {alpha}-alumina phase can form at anomalously low temperatures.

• Research Organization: Argonne National Lab., IL (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States); Electric Power Research Inst., Palo Alto, CA (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 434919
• Report Number(s): ANL/MSD/CP--91224; CONF-961040--15; ON: DE97001409; CNN: Contract RP 8041-05
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
ALUMINIUM OXIDES
CHROMIUM ALLOYS
IRON BASE ALLOYS
OXIDATION
SCALING
STRAINS