Effect of microstructure on material-removal mechanisms and damage tolerance in abrasive machining of silicon carbide

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1995.tb08683.x· OSTI ID:116097

Xu, H H.K.; Padture, N P; Jahanmir, S ^[1]

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1. National Inst. of Standards and Technology, Gaithersburg, MD (United States). Ceramics Div.

Effects of microstructural heterogeneity on material-removal mechanisms and damage-formation processes in the abrasive machining of silicon carbide are investigated. It is shown that the process of material removal in a conventional silicon carbide material with equiaxed-grain microstructure and strong grain boundaries consists of the formation and propagation of transgranular cracks which results in macroscopic chipping. However, in a silicon carbide material, containing 20 vol% yttrium aluminum garnet (YAG) second phase, with elongated-grain microstructure and weak grain boundaries, intergranular microcracks are formed at the interphase boundaries, leading to dislodgement of individual grains. These different mechanisms of material-removal affect the nature of machining-induced damage. While in the conventional silicon carbide material the machining damage consists of transgranular median/radial cracks, in the heterogeneous silicon carbide material, abrasive machining produces interfacial microcracks distributed within a thin surface layer. These two distinct types of machining damage result in a different strength response in the two forms of silicon carbide materials. In the case of the conventional silicon carbide, grinding damage results in a dramatic decrease in strength relative to the as-polished specimens. In contrast, the ground heterogeneous silicon carbide specimens show no strength loss at all.

• OSTI ID: 116097
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 9 Vol. 78; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CRACK PROPAGATION
CRACKS
FLEXURAL STRENGTH
GRAIN BOUNDARIES
INTERFACES
LAYERS
MACHINING
MICROSTRUCTURE
SILICON CARBIDES
SURFACES
YTTRIUM OXIDES