Determine Ti-6Al-4V orthotropic properties with NDT?
Determine Ti-6Al-4V orthotropic properties with NDT?
(OP)
I have a specimen of Ti-6Al-4V plate (approx. 3" x 3" x 5" with the grain in the 5" direction). I need to determine the 9 orthotropic properties (3 Young's moduli, 3 shear moduli, 3 Poissons ratios). However, I don't want to alter the specimen (e.g., for tensile tests). Can the orthotropic properties be determined by measuring the wave speed in the three directions with ultrasonic pulse echo? If so:
- Who could perform these tests?
- Where can I find literature that gives details and limitations of this test?
Are there other non-destructive tests that would give the properties?
Thanks,
Don Culp
- Who could perform these tests?
- Where can I find literature that gives details and limitations of this test?
Are there other non-destructive tests that would give the properties?
Thanks,
Don Culp





RE: Determine Ti-6Al-4V orthotropic properties with NDT?
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
Also, the properties can vary substantially depending on the manufacturing process (e.g., forging versus extruding), the material's form (sheet, rod/bar, plate), and the heat treatment. Hence, I need a method to determine the properties of my particular sample. Since I may need to run additional tests on my specimen I can't sacrifice this specimen to make tensile test specimens.
Thanks for any additional suggestions.
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
Aaron Tanzer
www.lehightesting.com
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
ht
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
http://www
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
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In this article (and in Barile's article that you reference), thin plates are used. For this case of plane stress only 4 material properties need to be adjusted in the FEM in order to get agreement with the ESPI (see page 6 of the above article). For the general 3D orthotropic case, 9 material properties must be adjusted which makes the process very much more difficult. Do you know anyone who uses this method for the general 3D case? I would be particularly interested in how the specimen is loaded for the ESPI and the sequence by which the properties are adjusted in the FEM.
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
htt
You may find Fig. 2 in the following link relevant as well:
http://ww
Maui
www.EngineeringMetallurgy.com
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
In your first link "Calculation of the Elastic Anisotropy of Ti:6Al-4V..." there is an interesting statement in the full text preview (just above the table): "The elastic constants for single crystal titanium have been determined ultrasonically by Flowers." Hence, an ultrasonic method may be possible.
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
But if the material you have was produced using standard industrial melting and processing techniques, then it is composed of a large number of radomly oriented grains. Using the pulse echo technique on such a material will provide you with an average value of the elastic constants over these various crystallographic orientations. For this reason, you won't be able to determine their values in specific crystallographic directions for the material that you have in hand using this technique.
Maui
www.EngineeringMetallurgy.com
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
I don't need the properties in specific crystallographic orientations. I need the properties in the longitudinal, long transverse, and short transverse material directions (i.e., the same as would be obtained using standard tensile tests on an orthotropic material). I will use these properties in FEA/FEM.
With this consideration, could pulse-echo be used on my unmodified specimen? If so, do you know who could provide this service?
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
V = [E/rho]^0.5
where V is the wave speed, E is Young's modulus, and rho is the density of the material. Where the material is anisotropic, the relationships become more complicated, as described here:
http:
I'd suggest contacting a certified level III ultrasonic operator and posing this question to them. They should be able to do it, or suggest someone who can.
Maui
www.EngineeringMetallurgy.com
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
The only way your going to get orthotropic properties in bar or plate stock is if you have a texture. It might be cheaper just to do an x-ray diffraction analysis by an outside lab on the material you have available to figure out the texture. Otherwise, I would try to measure the speed (as Maui said) of longitudinal waves in 3 directions.
Metalhead
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
metalhead -- I can measure the longitudinal wave speed in the three directions. However, how do I convert these wave speeds into the 9 material properties for an orthotropic material?
RE: Determine Ti-6Al-4V orthotropic properties with NDT?
Well the shear modulus should be determined analogously to Young's Modulus using shear waves. The only way to extract any info related to the Poisson ratio by ultrasonic tests is to send longitudinal waves each of the three axis while containing (dampen) the other two and measuring the speed. Of course, there are details that you will need to work out.
Metalhead