×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Converting hardness to fracture toughness
2

Converting hardness to fracture toughness

Converting hardness to fracture toughness

(OP)
Does anyone have the equation to convert hardness (vickers) to fracture toughness?  I would think it's only for certain materials but, could be a useful equation for me to have.  I will continue to look for it and will post it if I find it.  Thanks

RE: Converting hardness to fracture toughness

There is no such equation for converting hardness to fracture toughness.

RE: Converting hardness to fracture toughness

Agreed.  There is no quantitative relationship between frax toughness and hardness/tensile strength.  If you still need a rough guide read 'Rapid and Inexpensive Tests for Determining Fracture Toughness' report 328, 1976 by the National Material Advisory Board, and look at Figure 1.  

http://books.google.com/books?id=NGUrAAAAYAAJ&dq=Rapid+and+Inexpensive+tests+determining+fracture+toughness&printsec=frontcover&source=bl&ots=J8ZtoSy3Z8&sig=vuR63ImijZVCCSxvxc4bxRVaRz0&;hl=en&;ei=7OG3Ss3XD5KX8AbW88zBDQ&;sa=X&oi=book_result&ct=result&resnum=1#v=onepage&q=&f=false
  

RE: Converting hardness to fracture toughness

(OP)
Ah, yes you guys are right there is no exact conversion or relation, though maybe I ment there was a way to obtain a fracture toughness reading when doing a hardness test.  I just found the calculations and attached them in pdf.  It is based on using a macro vickers indent and measuring the cracks emanating from each corner.  Obvious, but still useful and neat.       

RE: Converting hardness to fracture toughness

Fracture toughness calculated from crack length during indentation testing is going to be limited to brittle materials.  Is this for a metal?  This technique is more suited to ceramics, where it has been developed more thoroughly.

RE: Converting hardness to fracture toughness

CoryPad;
The above software is apparently used on intermetallic compounds as one of several methods as indicated below

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TX8-3W7WF1J-5&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1020085499&;_rerunOrigin=google&_acct=C000050221&_version=1&;_urlVersion=0&_userid=10&md5=8c04d97f3ffdf9bbfa13014911259240

I don't see any application to typical metals or alloys. Amazing what a little internet leg work can do.
 

RE: Converting hardness to fracture toughness

I had past experience with this for ceramics; brittle intermetallic compounds would be an obvious extension.  The technique really isn't suited toward metals, so this topic would be better if placed in forum367: Material engineering other topics.

RE: Converting hardness to fracture toughness

(OP)
Yes, only for brittle materials (so mostly ceramics). It's obvious you need to have crack propagation to even do the calculation.  It could be moved, and might be very useful to someone.  I have heard the KIC SHETTY is the most commonly used also.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources