Re: Elastic Modulus

[ NDT-net Forum ]
[ Follow Ups ] [ Post Followup ] [ Help ]

Re: Elastic Modulus
Posted by: Udo Schlengermann (PID_172), E-mail: uschlengermann@krautkramer.de, on April 05, 2000 at 09:12 :
In Reply to: Elastic Modulus posted by : Anish Kumar on April 05, 2000 at 08:19:
reply by Udo Schlengermann To get reliable calculated values of elastic moduli E and G
1. you have to measure the velocities of longitudinal and transverse velocities on samples of your material.
This can easily be done by ultrasonic equipment.
You can not rely on values in tables.
The samples have to be big enough to allow for undisturbed wave propagation (much bigger than the sound beam).
2. Elastic moduli calculated from density and ultrasonic velocities are only valid for a half space and a strict elastic behaviour of the material.
If your samples are thin plates or small diameter rods
vibrational mode is different from half space and results therefore are differerent.
Also there are differences between mechanically measured values, e.g. by tensile tests, and calculated moduli using ultrasonic velocities.
Please, do not calculate ultrasonic velocities from mechanically measured elastic moduli. You get much lower velocities than by using ultrasonic waves directly.
Therefore again my recommendation: You have to measure the velocities on suited samples of your material.
Kind regards
Udo Schlengermann
------------
: I am working on microstructural characterization in metallic materials, such as ferritic steels, Inconel 625 superalloy etc., using ultrasonic measurements. Quite often, I need the elastic modulus values of various types of precipitates for uderstanding the change in ultraosnic velocity with precipitation, such as M23C6, Cr2N, and Fe2Mo (Laves phase) in steels and gamma prime, gamma double prime, delta and Ni2Mo type of precipitates in Superalloys. Is there some publication or record where I can get these values, or if some body can supply these values i will be very much thankful to him.
: Thanking You.
: Anish Kumar

Follow Ups:

Post a Followup:

Name:

E-Mail:

Subject:

Comments:
: reply by Udo Schlengermann <uschlengermann@krautkramer.de): : To get reliable calculated values of elastic moduli E and G : 1. you have to measure the velocities of longitudinal and transverse velocities on samples of your material. : This can easily be done by ultrasonic equipment. : You can not rely on values in tables. : The samples have to be big enough to allow for undisturbed wave propagation (much bigger than the sound beam). : 2. Elastic moduli calculated from density and ultrasonic velocities are only valid for a half space and a strict elastic behaviour of the material. : If your samples are thin plates or small diameter rods : vibrational mode is different from half space and results therefore are differerent. : Also there are differences between mechanically measured values, e.g. by tensile tests, and calculated moduli using ultrasonic velocities. : Please, do not calculate ultrasonic velocities from mechanically measured elastic moduli. You get much lower velocities than by using ultrasonic waves directly. : Therefore again my recommendation: You have to measure the velocities on suited samples of your material. : Kind regards : Udo Schlengermann : ------------ : : I am working on microstructural characterization in metallic materials, such as ferritic steels, Inconel 625 superalloy etc., using ultrasonic measurements. Quite often, I need the elastic modulus values of various types of precipitates for uderstanding the change in ultraosnic velocity with precipitation, such as M23C6, Cr2N, and Fe2Mo (Laves phase) in steels and gamma prime, gamma double prime, delta and Ni2Mo type of precipitates in Superalloys. Is there some publication or record where I can get these values, or if some body can supply these values i will be very much thankful to him. : : Thanking You. : : Anish Kumar

Optional Link URL: Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP

Link Title: is important! Information on my Home Page

Optional Image URL: http://www....gif

Attention! Please click the button only once. This may take a moment to process
[ NDT-net Forum ] [ Help ]

Optional Link URL:	Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP
Link Title: is important!	Information on my Home Page
Optional Image URL:	http://www....gif