Investigation of creep threshold stresses using in situ TEM straining experiment in an Al―5Y2O3―10SiC composite

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 527; no. 9; pp. 2390 - 2397
• Main Authors: DESHMUKH, S. P, MISHRA, R. S, ROBERTSON, I. M
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier 15-04-2010
• Subjects: Aluminum; Applied sciences; Creep; Creep (materials); Creep rate; Detachment; Dislocations; Dispersion hardening metals; Exact sciences and technology; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metal matrix composites; Metals. Metallurgy; Particulate composites; Powder metallurgy. Composite materials; Production techniques; Stresses; Threshold stress; Transmission electron microscopy; Dislocation-particle interaction; Creep; Metal matrix composite; Temperature effect; Aluminium; Creep rate; Composite material; Dispersion strengthened metal; Dislocation; Particle matrix interface; Silicon carbide; Transmission electron microscopy; In situ TEM; Yttrium oxide; Threshold stress
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2009.12.015

Creep behavior of metal matrix composites is similar to dispersion strengthen alloys and characterized by the presence of a threshold stress below which the creep rate is negligible. This threshold stress is attributed, at least in dispersion-strengthened alloys, to dislocation particle interactions in which the detachment of the dislocations from the particle is the rate-limiting step. Creep experiments were performed on an Al-5Y2O3-10SiC composite in the temperature range of 473 and 573K and the nature of the dislocation-particle interaction was determined by performing in situ straining experiments at elevated temperature in a transmission electron microscope. The threshold stress and the detachment stress are temperature dependent and the detachment stress is less than the threshold stress emphasizing the contribution of load transfer from the matrix to the reinforcement phase.