High-temperature deformation and defect chemistry of (La{sub 1{minus}x}Sr{sub x}){sub 1{minus}y}MnO{sub 3+{delta}}

Journal Article · Tue Aug 10 04:00:00 EDT 1999 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(99)00160-3· OSTI ID:684397

Cook, R E; Goretta, K C; Routbort, J L ^[1]; Wolfenstine, J ^[2]; Nash, P ^[3]

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1. Argonne National Lab., IL (United States)
2. Army Research Lab., Adelphi, MD (United States)
3. Illinois Inst. of Tech., Chicago, IL (United States). Dept. of Mechanical, Materials, and Aerospace Engineering

The creep behavior of (La{sub 1{minus}x}Sr{sub x}){sub t{minus}y}MnO{sub 3+{delta}} has been studied as a function of oxygen partial pressure (P{sub O{sub 2}}) and Sr concentration. Polycrystalline samples (x = 0.1, 0.2, 0.3) were deformed at 1,523 K in constant-crosshead-speed compression tests in various atmospheres (10{sup {minus}2} {le} P{sub O{sub 2}} {le} 10{sup 5} Pa). The material deformed by grain-boundary sliding accommodated by lattice diffusion with some possible cavitation and/or interface reaction control. The defect-chemistry model which is standard in the literature could not explain the dependence of the stress on P{sub O{sub 2}} and the Sr concentration. A modified defect-chemistry model shows that cation vacancies controlled the creep rate at P{sub O{sub 2}} {le} 10{sup 5} Pa for x = 0.3 and at low P{sub O{sub 2}} for x = 0.1 and 0.2, and that oxygen vacancies were rate-controlling at high P{sub O{sub 2}} for x = 0.1 and 0.2.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 684397
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 10 Vol. 47; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL COMPOSITION
CREEP
CRYSTAL DEFECTS
EXPERIMENTAL DATA
LANTHANUM OXIDES
MANGANESE OXIDES
OXYGEN
PRESSURE DEPENDENCE
STRONTIUM OXIDES
TEMPERATURE RANGE 1000-4000 K