Effects of yttria stabilized zirconia on transformation toughening of molybdenum disilicide composites

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:96572

Chen, L C; Brooks, D; Soboyejo, W ^[1]

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1. Ohio State Univ., Columbus, OH (United States)

The effects of yttria stabilization (0-6 mol%) on the fracture toughness of molybdenum disilicide composites reinforced with 20 vol.% yttria partially stabilized zirconia (Y-PSZ) particles are presented. It is found that the fracture toughness increased from 3.8 MPa{radical}m for the monolithic MoSi{sub 2} to 4.8-5.7 MPa{radical}m for the Y-PSZ reinforced composites. Examinations of the fractured specimens, using optical interference microscopy and laser Raman spectroscopy, showed that the stress-induced martensitic transformation of the Y-PSZ particles occurred only in the plastic wake of the composite stabilized with 2 mol.% yttria. However, the fracture toughness of the 2 mol.% Y-PSZ reinforced composite was in the same range as those of the other composites which did not exhibit evidence of transformation toughening. The results are rationalized using micromechanical models for the assessment of transformation toughening and microcrack shielding mechanisms.

• OSTI ID: 96572
• Report Number(s): CONF-940416--; CNN: Grant F49620-94-1-0107DEF
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
CRACKS
FRACTURE PROPERTIES
MICROSTRUCTURE
MOLYBDENUM SILICIDES
STRESS INTENSITY FACTORS
YTTRIUM OXIDES