Fracture, fatigue and indentation behavior of pyrolytic carbon for biomedical applications

R. O. Ritchie, R. H. Dauskardt, W. W. Gerberich, A. Strojny, E. Lilleodden

Research output: Contribution to journalConference articlepeer-review

6 Scopus citations

Abstract

The fracture, fatigue and indentation properties of pyrolytic carbon, both as a monolithic material and as a coating on a graphite substrate, are described in light of its use for biomedical implant applications, specifically for the manufacture of mechanical heart valve prostheses. From the perspective of determining properties that are important for the prediction of safe structural lifetimes in such prostheses, it is found that by traditional engineering standards, pyrolytic carbon has low damage tolerance, i.e., fracture toughness values between 1 and 3 MPa√m and susceptibility to subcritical crack growth by both cyclic fatigue and stress-corrosion cracking (static fatigue). Subcritical crack-growth rates are evaluated in simulated physiological environments for both through-thickness 'long' cracks, and for physically 'small' surface cracks, the latter measurements being performed for cracks initiated at hardness indents. The unusual deformation characteristics of indentation in pyrolytic carbon are described based on instrumented microhardness indentation and scanning probe microscopy (AFM/STM) studies.

Original languageEnglish (US)
Pages (from-to)229-254
Number of pages26
JournalMaterials Research Society Symposium - Proceedings
Volume383
DOIs
StatePublished - Jan 1 1995
EventProceedings of the 1995 MRS Spring Meeting - San Francisco, CA, USA
Duration: Apr 17 1995Apr 21 1995

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