All properties similar apart from Modulus - Why?
All properties similar apart from Modulus - Why?
(OP)
Hi there,
I'm currently running tensile tests between two pieces of 1050 Aluminum in non-hardened (80MPa) states. One piece has failed in service, the other has not.
I am measuring UT, Yield, Elongation and Youngs Modulus.
The UT and yields are similar between both, but the elongation is higher and the modului are lower in the failed piece.
Ignoring test set-up, and in-service reasons of failure, any ideas why this difference?
Thanks,
A101
I'm currently running tensile tests between two pieces of 1050 Aluminum in non-hardened (80MPa) states. One piece has failed in service, the other has not.
I am measuring UT, Yield, Elongation and Youngs Modulus.
The UT and yields are similar between both, but the elongation is higher and the modului are lower in the failed piece.
Ignoring test set-up, and in-service reasons of failure, any ideas why this difference?
Thanks,
A101





RE: All properties similar apart from Modulus - Why?
Mike Halloran
Pembroke Pines, FL, USA
RE: All properties similar apart from Modulus - Why?
Every Al alloy that I could look up has a modulus between 10 and 11 million psi.
Have you looked at micros? Any preferential grain orientation?
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Plymouth Tube
RE: All properties similar apart from Modulus - Why?
RE: All properties similar apart from Modulus - Why?
How much difference is there between the two samples? Elongation values that are within several percentage points is to be expected. Modulus is notoriously difficult to measure, and will certainly vary by several tenths, meaning 10.1 vs 10.5 million psi, even with the same alloy, processing, sample size, etc.
RE: All properties similar apart from Modulus - Why?
Elongation for the 'good' piece I'm getting 31%, 36% and 22%.
Modulus for the 'good' piece I'm getting 44.1GPa 45.48GPa and 57.2 GPa respectively. (Sorry I don't do Imperial!)
For the 'failed' piece I'm getting 42% 37% and 35%.
Modulus, 70.4Gpa, 42.2Gpa and 40.8Gpa.
I think the 70.4 is a bit of an anomalie, but the rest does suggest it's straining more than the 'good' piece.
Chemical composition is very similar using EDX.
RE: All properties similar apart from Modulus - Why?
The low numbers indicate to me that you have inaccurate testing.
Or the material my be yielding at very low strains. Either way the data is not telling you much. You need to look very carefully at the curves and determine what range in being used for the calculations.
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Plymouth Tube
RE: All properties similar apart from Modulus - Why?