Transformation, microcrack, and thermal residual stress as interactive processes in ZrO[sub 2]-toughened Al[sub 2]O[sub 3], simulated by the finite element method

Journal Article · Mon Aug 01 00:00:00 EDT 1994 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

OSTI ID:7103958

Zhonghua, Li; Yong, Zhao ^[1]; Schmauder, S ^[2]

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1. Xi'an Jiaotong Univ. (China). Dept. of Engineering Mechanics
2. Max-Planck-Inst. fuer Metallforschung, Stuttgart (Germany)

Some important aspects associated with the transformation, microcrack, and thermal residual stress in ZrO[sub 2]-toughened Al[sub 2]O[sub 3] are analyzed by a computer simulation based on the finite element method. These aspects include (1) the behavior of the transformation toughening, (2) microcracking in a thermal residual stress field, and (3) the interaction between transformation and microcracking. The following findings are confirmed by the numerical study. (1) The transformation within 120 deg fan ahead of the crack tip (frontal zone) gives rise to an amplification of stress intensity, whereas that behind this fan (wake zone) shields the crack tip. The effect of shielding is dominant. These trends are consistent with the continuum model. (2) The thermal residual stress does not give rise to an additional volume expansion, and hence, the dilation induced by the microcrack opening cannot be estimated from the relief of the residual tensile stress. (3) the transformation and microcracking in the frontal zone encourage each other, whereas in the wake zone, they suppress each other. As a result of this interaction, the combined toughening effect is lower than that estimated by simple superposition. Points (2) and (3) differ from the central hypothesis of the continuum model.

• OSTI ID: 7103958
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 25:8; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CRACK PROPAGATION
CRYSTAL-PHASE TRANSFORMATIONS
FRACTURE PROPERTIES
MECHANICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
RESIDUAL STRESSES
STRESS INTENSITY FACTORS
STRESSES
THERMAL STRESSES
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES