Incipient plasticity in 4H-SiC during qusistatic nanoindentation

Saurav Goel, Jiwang Yan, Xichun Luo, Anupam Agrawal

Research output: Contribution to journalArticle

20 Citations (Scopus)
382 Downloads (Pure)

Abstract

Silicon carbide (SiC) is an important orthopedic material due to its inert nature and superior mechanical and tribological properties. Some of the potential applications of silicon carbide include coating for stents to enhance hemocompatibility, coating for prosthetic-bearing surfaces and uncemented joint prosthetics. This study is the first to explore nanomechanical response of single crystal 4H-SiC through quasistatic nanoindentation. Displacement controlled quasistatic nanoindentation experiments were performed on a single crystal 4H-SiC specimen using a blunt Berkovich indenter (300 nm tip radius) at extremely fine indentation depths of 5 nm, 10 nm, 12 nm, 25 nm, 30 nm and 50 nm. Load–displacement curve obtained from the indentation experiments showed yielding or incipient plasticity in 4H-SiC typically at a shear stress of about 21 GPa (~an indentation depth of 33.8 nm) through a pop-in event. An interesting observation was that the residual depth of indent showed three distinct patterns: (i) positive depth hysteresis above 33 nm, (ii) no depth hysteresis at 12 nm, and (iii) negative depth hysteresis below 12 nm. This contrasting depth hysteresis phenomenon is hypothesized to originate due to the existence of compressive residual stresses (upto 143 MPa) induced in the specimen by the polishing process prior to the nanoindentation.
Original languageEnglish
Pages (from-to)330-337
Number of pages8
JournalJournal of the Mechanical Behavior of Biomedical Materials
Volume34
Early online date12 Dec 2013
DOIs
Publication statusPublished - 2014

Keywords

  • nanoindentation
  • plasticity
  • elastic response
  • SiC

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