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

Journal Article · · Acta Materialia
The creep behavior of (La{sub 1-x}Sr{sub x}){sub 1-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 1523 K in constant-crosshead-speed compression tests in various atmospheres (10{sup -2}{<=}P{sub O{sub 2}}{<=}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}}{<=}10{sup 5} Pa for x=0.3 and at low {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)
Sponsoring Organization:
SC
DOE Contract Number:
AC02-06CH11357
OSTI ID:
942537
Report Number(s):
ANL/MSD/JA-32349
Journal Information:
Acta Materialia, Journal Name: Acta Materialia Journal Issue: 10 ; 1999 Vol. 47; ISSN 1359-6454; ISSN ACMAFD
Country of Publication:
United States
Language:
ENGLISH