Hi, all.

I have questions on the Young's modulus measurements of electroplated nickel
samples I did today. MTS machine with 150 kN load cell was used for tensile
testing. The original 135 mm diamater nickel sample was made from electroplating
of nickel (3.5 mm thick) at 20 mA/cm^2 in nickel sulfamate bath. Then the large
nickel sample was machined into pieces of 100 mm long, dog-bone shaps based on
the ASTM standard. The thickness was reduced to 3 mm, the length of the reduced
section was 32 mm, and the width of the reduced section was 6 mm. Those values
were entered prior to the MTS tensile testing. I used a pulling speed of 0.5, 1,
2 mm/min and pulling was done until the machined piece broke in half.

Then I got a data with stress (MPa) and strain (%). The perplxing thing I found
was that the Young's modulus caculated from the slope using the MST software
based on the measurements was just 10 GPa. With different pulling speed, the
data remained at the close range of 10 GPa. And even when I checked with
extracted data file, the data was similar. Interestinlgy, the yield strength was
in the range of 700 MPa for all three samples.

Does anyone know why I got this small Young's modules? Is the load cell too big
for the measurements?

Anyway I am going to buy a bulk nickel piece, have it machined into the same
shapes, and measure the Young's modulus using the same setup again. I hope
anyone who knows about the issue I brought up can provide some helpful ideas.

Thanks in advance,
Daniel